Last updated: April 28, 2026

Slack Image Size Cheat Sheet 2026

Q: What size should Slack custom emoji be?

Slack custom emoji should be square; 128x128 pixels is the practical target for crisp rendering. Supported formats are PNG, GIF, and JPEG, and Slack recommends keeping images under 128 KB. Slack will resize larger images, but uploading at 128x128 gives predictable results.

Q: How do I add a custom emoji to Slack?

Here's how: Resize your image in FastEdit using the Slack Emoji preset, then go to your Slack workspace, click the emoji icon in the message box, select "Add Emoji," upload your file, and give it a name. Workspace admins may restrict who can add emoji.

Q: Can Slack emoji be animated?

Yes. Animated GIF files at 128x128 pixels and under 128 KB work best as custom emoji. The animation plays automatically in messages. Keep frame counts low to stay under the size target.

Q: What is the Slack profile photo size?

Slack recommends 512x512 pixels for profile photos. The image is displayed at various sizes across the app, from 24px in compact mode to 512px in the profile view. Use a square image with the subject centered.

Slack custom emoji should be square, ideally 128x128 pixels, in PNG or GIF format, under 128 KB. While Slack will resize larger images, uploading at the target dimensions ensures crisp rendering across desktop and mobile. FastEdit makes it easy to crop, resize, and optimize images for Slack in one click.

Start editing Slack Custom Emoji

Pick this preset, drop your file, and FastEdit starts from the Slack Custom Emoji dimensions, format, and file-size target.

Slack Image Size Cheat Sheet

Custom Emoji

128x128 PNG / GIF Max 128 KB

Workspace custom emoji. Square aspect ratio required. Transparent backgrounds are supported with PNG format. GIF emoji can be animated.

Open Slack Custom Emoji preset →

Profile Photo

512x512 PNG / JPEG Max 1 MB

Workspace profile picture. Displayed at various sizes in messages, sidebars, and profiles. Square crop recommended.

Open Slack Profile Photo preset →

What can you create for Slack?

Use these rows when you know the asset you need but not the exact settings. Each one points to the matching FastEdit workflow.

How to prepare Slack Custom Emoji

Open FastEdit with the Slack Custom Emoji preset selected, drop your file, then export to this row's target: 128x128, PNG / GIF, max 128 KB.

slack custom emoji sizeslack custom emoji dimensionsresize slack custom emojicreate slack custom emoji

Open Slack Custom Emoji preset →

How to prepare Slack Profile Photo

Open FastEdit with the Slack Profile Photo preset selected, drop your file, then export to this row's target: 512x512, PNG / JPEG, max 1 MB.

slack profile photo sizeslack profile photo dimensionsresize slack profile photocreate slack profile photo

Open Slack Profile Photo preset →

Before you upload

Use PNG with transparency for emoji that need to blend into Slack's message background.
Keep emoji designs simple with bold shapes: they render as small as 22px in message text.
Animated GIF emoji are supported but tend to be distracting in busy channels: use sparingly.
Slack displays profile photos as small as 24px in compact view, so avoid fine detail and small text.

FAQ

What size should Slack custom emoji be?

How do I add a custom emoji to Slack?

Can Slack emoji be animated?

What is the Slack profile photo size?