Emojis and reaction GIFs make Slack better. Here’s how to create them.

Make sure you’ll always have the perfect reaction.

Since working from home became a new reality for a lot of us, communication has not been as easy as it used to be. Yes, we still have video calls where we can see our colleagues’ faces and gestures, but the bulk of our conversations happen through text—with no intonation, no playfully raised eyebrows, no finger guns. Just bland fonts and static profile pics.

This is exactly why emojis are so useful in conveying emotion and intent. The perfect one can insure against misinterpretation, while a poor choice may give a message an entirely new meaning. If your team works with Slack, you can choose from the classic Unicode emojis (the ones that live on your phone and everywhere else) but we know your feelings extend far beyond ? and ? . There’s literally no reason to settle when you can easily make your own.

Depending on how much work you want to do, you can use either a JPEG or GIF format, but when you’re done, you’ll be able to make your coworkers laugh with perfectly-timed reactions (fire-elmo.gif), or let them know how you feel about that presentation they asked you to do at 4:30 p.m. on Friday (disaster-girl.jpeg).

Slack emojis for beginners: the JPEG

photoshop
Your favorite meme deserves to be a Slack reaction. Start by cropping. Sandra Gutierrez G.

If you know how to snap a photo and do basic edits such as cropping and changing brightness and contrast, you are perfectly capable of making a Slack emoji.

The platform limits the image size you can use to 128KB and encourages square pics with transparent backgrounds, but these instructions are somewhat flexible. If you use a bigger file, Slack will automatically resize it to fit—I uploaded an 811KB photo (3000 x 1800 pixels) and the program didn’t even stutter. The ratio is also not an issue, as Slack will use your image’s width and paint the remaining space (above and below) black. It’s not the best aesthetic, but if you need to deliver a punchline quickly, it’s worth a shot. Don’t worry about transparent backgrounds either. If you can’t be bothered to cut along the outline of whatever you want to use as an emoji, or don’t know how, using a square photo will still work.

Although these inelegant solutions will be technically successful, they may be one-hit wonders, doomed to spend eons at the bottom of the list of customized emojis. If you want to make something your colleagues will share and appreciate, you have to do it right. If you have access to Adobe Photoshop, use that, but if you don’t, Photopea is a great free browser-based dupe that even shares some shortcuts with Photoshop. It will also save you from asking the IT guy for the admin password to your computer.

Crop your image

Using the crop tool (shortcut C on PS and Photopea), change the ratio of your picture to be 1-to-1. On both platforms, you’ll get options on the navigation bar at the top—on Photoshop choose 1 : 1 Square on the left. On Photopea click the dropdown menu under Free and choose Fixed ratio, then put 1 in the next two fields, W and H. This will allow you to cut your image into a perfect square. Just enlarge or reduce the selection to what you want and hit enter to finish.

Emojis are usually very small on Slack, so you’ll want to be strategic. Make sure the main focus of your emoji takes up as much space as possible. Any details might be too tiny to see, so try to go for a single face or object, and center on it.

Remove the background
Magic wand
There’s no tool that will magically get rid of the background, but the magic wand on Photoshop can help. Sandra Gutierrez G.

There are two easy ways to do this—the magnetic lasso and the magic wand.

Photopea doesn’t have a magic wand option, so the magnetic lasso will be your weapon of choice. To find it, hit the L key three times or click and hold the lasso icon on the dropdown menu (it’s third from the top on the left sidebar). The last variation with a magnet on it is the one you want. This tool draws a selection path around similar pixels and sets it in place by dropping tiny squares called anchor points. This works great when you have a clearly delineated figure, but not when the colors of the background are too similar to those that make up your emoji.

As you guide it, the lasso will sometimes deviate from where you want it to go. If that happens, just move your mouse to get it back on track. If the tool already has an anchor point in place, you can remove it by hitting Delete on your keyboard (Command + Delete on a Mac). You can also drop anchor points at will by left-clicking your mouse. This is especially handy when the line changes direction abruptly, like at a corner or sharp edge.

It may seem counterintuitive, but your goal here is to select everything you don’t want to keep in your emoji. For example, I traced the outline of the This is Fine meme (from the webcomic Gunshow by KC Green), and when I hit the bottom edge of the image, I started tracing its frame. Once you finish, close the lasso by clicking on the first anchor point. Then hit delete to remove everything inside.

Photoshop users may want to use the Magic Wand tool (W). Similar to the magnetic lasso, the magic wand automatically detects and selects clusters of similar pixels. Click on an area to select it, then hit delete to remove it. You can click and delete until the background is gone, or you can select as much of it as possible in one go by clicking while holding Shift. You’ll see the tool’s icon change into a magic wand with a plus sign—this will add a new selection to a previous one, making it bigger as you click. Once you’ve selected all you want, hit delete to get rid of it.

The main caveat with this tool is that it doesn’t work well when the image has a lot of gradients instead of solid colors. Such an image will make it hard for the tool to tell the background from the foreground, and you might need to click even the smallest patches of color to select them. In this case, the lasso will be a more efficient option.

Whatever tool you choose, use the eraser tool (E on Photoshop and Photopea) to delete any leftover pixels. Remember this is a small emoji, so it doesn’t have to be perfect.

Resize your image

No matter their original dimensions, all JPEG emojis in Slack display at the same size, so there’s technically no need to resize. Still, if you want to follow internet best practices, go ahead and resize it. A good rule of thumb is to keep your emojis no bigger than 300 x 300 pixels.

Take your Slack emojis to the next level: the GIF

PSD file
The monkey puppet meme. A true classic. Sandra Gutierrez G.

Thanks to Slack’s integration with Giphy and automatic previews of pasted URLs, you can insert GIFs directly into your messages. But you can also use these animated images to create emojis, and if JPEGs help you express yourself, you’ll realize reactions are even better when they come in GIF form.

Editing GIFs is simple, but it can be tedious and you need to know what you’re doing. If you have some time on your hands or are willing to procrastinate some of your chores for the sake of a GIF that will crack up your coworkers, it can be worth it.

Choose your fighter and resize it

Whether you want to turn your favorite GIF into an emoji or you caught your boss on video making a particularly funny face worthy of immortal life as a shareable meme, your first stop will always be an editing tool. There are platforms online that’ll help you format your GIF file, like Ezgif or Gifntext, but image editing programs like Photoshop and Photopea will give you more control.

Unlike JPEG emojis, size matters when it comes to GIFs. That 128KB cap can be an annoying hurdle to creating animated reactions, so it’s important to make it simple and light. If you’re starting with a video, make sure to keep it as short as you can—ideally 2 to 3 seconds—and resize the frame to a small 1-to-1 square.

Cameras on top-of-the-line smartphones like the iPhone 11 or Pixel 4 will take high-quality video in formats from 1920 x 1080 pixels to 3042 x 4032 pixels. If you kept any of these image sizes, it’d be difficult (if not impossible) to get the final GIF down to 128KB. If you want your own version of a GIF that already exists, find it online and download it. It’ll probably already be optimized for the web, but if it’s not, you’ll still need to make it smaller and lighter.

Edit your GIF

When using Photoshop or Photopea, notice the Layers tab as you open your file. You’ll see the programs separate the image into different layers representing the frames in your GIF—this means you can treat each one as an individual image. You’ll have one layer per frame in your GIF, so the more there are, the longer, higher-quality, and heavier a file will be.

As with JPEGs, Slack recommends square images with no background. You can do this by cropping and deleting the background for each layer. You can also add text, images, or drawings, and change colors and other image values, like contrast and brightness. Just keep in mind that whenever you edit a layer, you’re editing a single frame. If you want a change to show throughout the GIF, you’ll need to do it on every layer.

On Photopea, layers double as frames, so any editing you make will show directly on your GIF when you save it—including the removal of layers. You won’t be able to customize the duration of each frame, but if you want to keep it simple, this platform can be more than enough.

On Photoshop, however, layers are not actual frames, which is slightly confusing. To see the frames, you’ll need to look at the Timeline tab. Don’t worry if you can’t find it—it’s not displayed by default. To see it, head to the top navigation bar, go to Window, and click on Timeline in the dropdown menu.

Each frame has a specific duration (usually 0.2 seconds), which is one of the variables that determine your GIF’s duration. You can edit frames individually or in bulk—select the frames you want to edit by clicking on them (or select them all by clicking the first one and holding Shift while clicking on the last one), then click on the number below each frame. A dropdown menu will appear and you’ll be able to choose from a range of options, from no delay to a 10 second pause between frames. You can customize this field by clicking Other… .

Another way to alter the duration of your GIF is by cutting the number of frames. Doing this can make it look a bit more choppy, so cuts need to be well-distributed. Select the frames you want to remove and click the trash can icon on the bottom to delete them. Click the play button on the left to make sure your GIF flows properly.

I chose the monkey puppet meme and arbitrarily cut the amount of frames in half by getting rid of the odd-numbered frames. The change is barely noticeable—even less so considering the small display on Slack. Use this tool to fine-tune the beginning and end of your GIF, so you can have as few frames as possible.

You’ll also be able to use the Timeline tab to determine how many times you want your GIF to loop: click on the dropdown menu at the very bottom of the tab. It’s labeled Forever by default.

Save your GIF

After you’ve dedicated potentially half a workday to editing your GIF, it’s time to save it.

On Photopea, go to File, Export as, and choose GIF. In the dialog box that pops up, you’ll find a couple settings you can play around with to further edit your emoji, including image size and looping options. You’ll also be able to see how changing each of these variables affects the final file size, so you can more easily keep things below 128KB.

On Photoshop, go to File, Export, and choose Save for Web (Legacy)… . You’ll have the same options Photopea offers plus a couple more that may come in handy. These include choosing the size of your GIF’s color palette (fewer colors means a lighter file and a more lo-fi look) and whether you want a white background or full-on transparency. You’ll also be able to see how each of these variables affects the final kilobyte count, so you can have the perfect balance of quality and file size.

On either program, click Save when you’re done.

Upload your new emoji
Slack thread
It comes to a point where words are just unnecessary. Sandra Gutierrez G.

Congratulations—the hard part’s over and you’re almost there. Now it’s time to show your workspace your elite skills.

Before sharing your creation though, stop to think about what you’re posting. Everyone in your workplace can see and use the Slack emojis you create, including your boss and anyone who might be able to make your work life more difficult. If you have even the slightest suspicion that your new emoji might offend someone, save yourself some trouble and abstain from uploading it.

If, however, you’re sure your emoji is harmless, go ahead and share it. Click the emoji icon on any Slack window and then the Add Emoji button on the bottom left. The resulting popup window provides instructions for adding your new creation, but it’s as simple as choosing Upload Image, searching for the file on your hard drive, and uploading it. Slack will show you a preview, and ask you to give your emoji a name. Choose something specific, as it has to be unique. If you need more than one word, use hyphens instead of spaces. Click Save and you’re done.

You’ll be able to use your emoji as part of your messages or as a reaction by searching for it on the emoji menu, or by typing a colon immediately before the name.

If you decide to remove your emoji, you can do so by clicking the name of your workspace at the top of the left sidebar and choosing Customize. You’ll be able to find your icons by scrolling down the list or typing the name of your emoji. You can also type in your name to see all the files you’ve added. Click the X button on the right to delete an emoji.

Even when you can’t hear your colleagues’ laughter across the office, there’s definitely some satisfaction in making people giggle during the workday—even if it’s just for a bit. Feel free to experiment and express yourself with new and improved reactions, and may you long reign as the official Slack jester.

Sandra Gutierrez G.

Sandra Gutierrez G.is a Chilean journalist and the assistant DIY editor at PopSci. She has previously worked as an editor for MSN.cl, and a reporter for Rolling Stone magazine. When she's not putting baking soda on things, she's walking her 10-year-old beagle, Lucas. Contact the author here.