Choosing the right image format can cut file sizes by 50–80% without any visible quality loss. The wrong format bloats your pages, slows your site, and wastes storage. Here's exactly when to use each format and how to convert between them.
The main image formats explained
JPEG / JPG — Best for photos
JPEG uses lossy compression — it permanently discards some image data to achieve smaller file sizes. Each time you save a JPEG, it loses a little more quality.
Use JPEG when:
- Photographs with many colors and gradients
- File size matters more than perfect quality
- You don't need transparency
- Images for web use, email, or social media
Avoid JPEG when:
- Images have text, logos, or sharp edges (compression artifacts become visible)
- You need transparency (JPEG doesn't support it)
- You'll edit and re-save the image multiple times
PNG — Best for graphics with transparency
PNG uses lossless compression — no image data is discarded. PNG also supports transparency (alpha channel), making it essential for logos, icons, and overlays.
Use PNG when:
- Logos, icons, illustrations with sharp edges
- Images with transparent backgrounds
- Screenshots of text or UI
- Images you'll edit further (no quality loss on save)
Avoid PNG when:
- Photographs (file sizes are much larger than JPEG for photos)
- Bandwidth is a concern
WebP — The modern web standard
WebP achieves roughly 25–35% smaller file sizes than JPEG at equivalent quality, and also supports transparency like PNG.
Use WebP when:
- Building modern websites (all major browsers support WebP since 2020)
- You want the best balance of quality and file size
- You need transparency but want smaller files than PNG
Avoid WebP when:
- Sending images to people who may open with older software
- Submitting to platforms or CMSs that don't accept WebP
GIF — For simple animations
GIF supports animation but is limited to 256 colors. For complex animations, modern alternatives (animated WebP, video) are much more efficient.
AVIF — The next generation
AVIF achieves even better compression than WebP. Browser support is growing (Chrome, Firefox, Safari 16+) but not yet as universal as WebP.
Format comparison at a glance
| Format | Compression | Transparency | Animation | Best for |
|---|---|---|---|---|
| JPEG | Lossy | No | No | Photos |
| PNG | Lossless | Yes | No | Graphics, logos |
| WebP | Both | Yes | Yes | Web images |
| GIF | Lossless | Partial | Yes | Simple animations |
| AVIF | Lossy | Yes | Yes | Next-gen web |
When conversion causes quality loss
| Conversion | Quality loss? |
|---|---|
| JPEG → PNG | No new loss (but JPEG artifacts are preserved) |
| PNG → JPEG | Yes (lossy compression applied, transparency lost) |
| PNG → WebP lossless | No |
| JPEG → WebP | Yes (re-encoding); use 90%+ quality to minimize |
| Anything → PNG | Never (lossless output) |
Best practice: Always convert from the highest-quality source. Avoid JPEG-to-JPEG re-save chains.
Converting for specific platforms
- Web: WebP primary, JPEG fallback for photos
- Instagram: JPEG at 1080px wide, 85%+ quality
- Email: JPEG (safest cross-client compatibility)
- Print: PNG or TIFF (lossless); avoid JPEG for print
How to convert images free
- Go to Image Converter
- Upload your image (JPG, PNG, WebP, GIF, or BMP)
- Select the output format
- Adjust quality if converting to a lossy format
- Download the converted image
All conversion happens in your browser — your image is never uploaded to any server.