What size is a Slack workspace icon?

Slack workspace icons should be 512×512 pixels. The image is displayed as a square with slightly rounded corners in the Slack sidebar.

What size is a Slack profile photo?

Slack profile photos display at various sizes but should be uploaded at 512×512 pixels for best quality across all views, from 24px to 512px.

What size are Slack custom emoji?

Slack custom emoji must be under 128×128 pixels and under 64KB in file size. PNG format with transparency is recommended.

Are my images uploaded to a server?

No. All processing happens entirely in your browser using the Canvas API. Your images never leave your device.

What size is a Slack app icon?

Slack app icons for directory listings must be 512×512 pixels in PNG format. This icon appears in the Slack App Directory and on the app's About page inside Slack.

Does Slack support transparent backgrounds in images?

Transparency is supported for custom emoji (PNG with alpha channel). Workspace icons and profile photos are displayed against Slack's sidebar background, so transparency is not recommended for those.

Slack Image Resizer — Resize Photos for Slack

Why Use This Tool?

Slack is the workplace communication platform — every image here represents your professional brand. Workspace icons appear in the Slack sidebar and are often the first thing clients or team members associate with your organization. Custom emoji are a key part of team culture, and proper sizing ensures they're legible in the Slack interface.

Slack Image Size Guide (2026)

Image Type	Size (pixels)	Aspect Ratio	Notes
Workspace Icon	512×512	1:1	Displayed with rounded corners
Profile Photo	512×512	1:1	Appears at many sizes from 24px up
Custom Emoji	128×128	1:1	Max 64KB, PNG recommended
App Icon	512×512	1:1	For Slack app directory listings

Privacy First — 100% Client-Side

Your images are processed entirely in your browser using the HTML5 Canvas API. Nothing is uploaded to any server. You can verify this by disconnecting from the internet after loading the page — the tool works offline.

Tip: Slack workspace icons appear at many sizes — as small as 18px in some notification views. Keep your workspace icon simple: your company's main logo mark (not the full wordmark) in a clean, square format works best.

Tips for Slack Images

Workspace icons represent your company — use your official logo mark in a square format. Ensure it has good contrast against both light and dark sidebars.
Profile photos in Slack are visible in threads, reactions, DMs, and user lists. A clear headshot or consistent avatar helps teammates identify you quickly.
Custom emoji (under 128×128, max 64KB) — keep them simple. Emoji appear at 22×22px in message text. Use PNG with transparency so they blend into the chat background.
Slack's dark mode means your images need to work on both light and dark backgrounds — test both before finalizing.
For enterprise Slack, workspace branding is important for multi-channel partner (MCP) use cases — your workspace icon may be seen by external organizations.