Tumblr Image Sizes — Photo Post, GIF, Header & Avatar

Photo Posts

Tumblr states two numbers, and they are the same shape. It recommends 540 pixels wide by 810 tall so images are not scaled down on the dashboard, and it serves a full-size version of up to 2048 pixels wide and 3072 pixels tall when someone clicks through. Both are 2:3 — so one 2:3 master covers both the dashboard render and the click-through.

• Design at 2048x3072, let Tumblr derive the rest: upload the full-size 2:3 master. Tumblr generates the 540px dashboard render from it, so you get a sharp click-through for free.
• 540px is the column, not the limit: the dashboard column is what almost everyone sees. Anything that has to be legible — captions inside the image, thin type, chart labels — must survive being rendered at 540 wide.
• 2:3 is portrait: Tumblr’s dashboard is a single vertical column, so tall images occupy more of the screen than wide ones. A landscape photo is not wrong, it just wins less real estate.
• 20MB per static image: the ceiling for JPEG, PNG, and WEBP. It is generous enough that it never binds in practice — dimensions bind first.
• 10 images from the apps, 30 from the web: the per-post cap depends on where you post from, which is worth knowing before you build a 20-image photoset on your phone.

GIFs

Tumblr is the platform GIFs were built for, and it is the one spec people get wrong most often — because the number everyone quotes (10MB) is the ceiling, not the target. There are three thresholds, and the one that matters sits at 5MB: if Tumblr cannot serve a GIF above it, it shows only the first frame. Your animation silently becomes a still.

• 540 pixels wide, maximum: Tumblr recommends GIFs be no more than 540 wide — the dashboard column width. A wider GIF is a bigger file for no visible gain.
• Under 3MB is the real target: below it, Tumblr leaves your file alone. Above it, you are trusting Tumblr’s compressor with your dithering and colour palette.
• The 5MB cliff: a GIF over 5MB that Tumblr cannot successfully compress is served as its first frame only. This is the failure everyone has seen and nobody can explain.
• Pre-compress before you upload: if you are handing Tumblr a compressed GIF, keep it under 5MB. Cut frames, drop the frame rate, or reduce the palette — all three beat letting the compressor guess.
• Everything becomes GIFV: Tumblr transcodes uploads regardless. The GIF you upload is a source file, not the file that gets served.

Header Image

Tumblr publishes an ideal header of 2048x1152 pixels — a clean 16:9 — at up to 10MB, in JPEG, PNG, WEBP, or GIF.

• 2048x1152, 16:9: the ideal size Tumblr states. Any 16:9 image scales to it cleanly.
• Centre what matters: the header crops differently across themes, desktop, and mobile. Keep logos and text away from the edges, and expect the avatar to sit on top of it.
• GIFs are allowed here: the header is the one profile asset that accepts an animated GIF. Avatars do not.
• 10MB ceiling: the same limit as the avatar, and a fifth of what a photo post allows.

Avatar

The blog avatar — Tumblr calls it the blog icon — has an ideal size of 128x128 pixels, up to 10MB, in JPEG, PNG, or WEBP.

• 128x128, square: the size Tumblr states outright. Upload a square or Tumblr crops one for you.
• No animated avatars: the accepted formats are JPEG, PNG, and WEBP. GIF is not among them — that is the header’s privilege.
• It renders small, and it renders everywhere: the avatar sits beside every post you make and reblog. At 128 pixels a wordmark is unreadable; a single high-contrast shape is not.
• Round or square depends on the theme: keep anything load-bearing away from the corners so it survives a circular mask.

Frequently Asked Questions