Instagram image sizes — every format, in one cheat sheet

Picking an image format used to be simple: JPG for photos, PNG for screenshots, done.In 2026 that mental model leaves real bandwidth — and real performance — on the table. This article walks through the three formats you'll actually ship in production this year.

The contenders

Modern browsers support three serious lossy formats: JPEG, WebP, and AVIF. PNG is still around for true lossless work but rarely wins the file-size fight for photographic content.

• JPEG — universal, ~30 years old, baseline.
• WebP — Google, ~25–30% smaller than JPEG at equal quality, supported everywhere except very old iOS.
• AVIF — newer, ~30% smaller than WebP at equal quality, slower to encode, supported in all evergreen browsers.

The numbers (12-image test set)

We took a set of twelve real-world images — product photos, hero illustrations, screenshots — and re-encoded each at quality 78. Here's the average:

format    │ size     │ vs JPEG
──────────┼──────────┼────────
JPEG      │ 312 KB   │ —
WebP      │ 224 KB   │ −28%
AVIF      │ 154 KB   │ −51%

Quality-perception note

At quality 78 all three formats are visually indistinguishable for typical photographic content on a 2x display. Below 60, WebP and AVIF hold up significantly better than JPEG, where blocky 8×8 DCT artifacts become visible.

The fastest image is the one your visitor never has to download.

What we recommend

1. Use AVIF as the primary format with a WebP fallback inside <picture>.
2. Keep a JPEG source-of-truth — old email clients still need it.
3. Compress at quality 76–80. Below 70, you're trading visible quality for bytes that don't matter.

You can do all of this without leaving your browser — drop a file into our compressor, pick AVIF, and ship. No upload, no roundtrip, no signup.