Collect emoji in your cart, choose For Slack or For Discord, and download the zip. Every file comes out named, sized and typed the way that app wants, so uploads don't bounce.
Slack
Unzip emoji-for-slack.zip.
In Slack, click your workspace name, then Tools & settings → Customize workspace.
Open the Emoji tab and click Add custom emoji.
Upload one file and give it the file's name (without the extension). That's the :name: people type.
Repeat for each file. Slack adds custom emoji one at a time.
Slack wants square images up to 128KB; the Slack zip keeps every file under that and at most 128px. If you can't see Add custom emoji, your workspace limits who can add them, so ask an admin.
Discord
Unzip emoji-for-discord.zip.
Open your server's menu, then Server Settings → Emoji.
Click Upload Emoji and select the files. You can pick several at once.
Discord names each emoji after its file; rename any you like.
Discord takes files up to 256KB with names of 2 to 32 letters, numbers or underscores; the Discord zip already follows those rules. Servers have a limited number of emoji slots, more with Server Boosts, and you need the Manage Expressions permission.
Good to know
Why not just save the image?
Every file here ends in .png, but about half are really GIFs or JPEGs, and both apps reject a file whose extension doesn't match. Downloads from the cart and the tile buttons fix the extension for you.
Do animated emoji still move?
Yes. Animated GIFs are kept as they are; only oversized still images get shrunk.
