cheat sheet
The Ultimate Image File-Size Reference
How big should that image be? Practical KB / MB benchmarks for every use case.
"How big should this image be?" is the most-asked question in web performance. The honest answer is: it depends on use case. Here's the practical reference.
Hero / above-the-fold images
| Type | Target size | Format |
|---|---|---|
| Full-width hero (desktop) | 150-300 KB | WebP / AVIF |
| Mobile hero | 80-150 KB | WebP |
| Lazy-loaded below fold | up to 500 KB | WebP / JPG |
Thumbnails / listing images
| Type | Target size | Format |
|---|---|---|
| Product grid thumbnail (300×300) | 15-40 KB | WebP / JPG |
| Article preview (640×360) | 30-80 KB | WebP |
| Avatar (96×96) | 5-15 KB | WebP / PNG |
Social media uploads
Most platforms re-compress aggressively, so over-optimizing on your end is wasted. Aim for "high quality" rather than "smallest possible":
| Platform | Recommended upload size |
|---|---|
| 1.5-3 MB (they re-compress to ~150 KB) | |
| Twitter / X | under 5 MB; over that = forced re-compress |
| under 1 MB for posts | |
| under 5 MB; PNG for logos, JPG for photos |
Wallpapers (when stored locally)
Phone storage is huge — quality matters more than size:
| Resolution | Reasonable JPG size |
|---|---|
| HD (1280×720) | 200-400 KB |
| Full HD (1920×1080) | 400-800 KB |
| 4K (3840×2160) | 1.5-3 MB |
| 5K (5120×2880) | 3-6 MB |
| 8K (7680×4320) | 6-12 MB |
Email signatures and embedded graphics
| Use case | Target size |
|---|---|
| Email signature image | under 50 KB |
| PDF embedded image | under 200 KB |
| Slide deck image | under 500 KB |
Tools to hit the target
- JPG compressor — slider-based, see KB live as you adjust quality.
- WebP converter — typically 30-50% smaller for the same quality.
- Resizer — smaller dimensions = smaller file. Resize first, compress second.
- Bulk mode — apply your target settings to a whole folder.
Try our free tools
- Image resizer — pixel-perfect downscale + upscale.
- Convert to WebP — 30-50% smaller files than JPG.
- Background remover — one-click cutout.
- Social-media resizer — every platform's exact dimensions.
- Bulk processing — apply any tool to up to 200 images at once.
Browse the full tool catalog or our other guides.
