There are dozens of image formats, and choosing the wrong one can mean bloated file sizes, lost transparency, degraded quality, or outright incompatibility. The format you pick matters — for web performance, for print quality, and even for whether someone else can open the file at all.
This guide covers every major image format, explains when to use each one, and shows you how to convert between them using BestPNG's free tools.
The Major Image Formats Explained
PNG (Portable Network Graphics)
- Compression: Lossless
- Transparency: Full alpha channel
- Best for: Logos, icons, screenshots, graphics with text, images requiring transparency
- File size: Moderate to large
PNG is the go-to format when you need perfect quality and transparency. Every pixel is preserved exactly. The tradeoff is larger file sizes compared to lossy formats like JPG or WebP.
JPG / JPEG (Joint Photographic Experts Group)
- Compression: Lossy
- Transparency: No
- Best for: Photographs, images with complex color gradients
- File size: Small
JPG is the universal format for photographs. Its lossy compression dramatically reduces file size with minimal visible quality loss at high settings. It does not support transparency — transparent areas are filled with white.
WebP
- Compression: Lossy or lossless
- Transparency: Yes
- Best for: Web images (replaces both JPG and PNG on websites)
- File size: Very small
Developed by Google, WebP offers 25-35% smaller files than PNG (lossless mode) and comparable savings over JPG (lossy mode). All modern browsers support it, but some desktop software and services still don't.
AVIF (AV1 Image File Format)
- Compression: Lossy or lossless
- Transparency: Yes
- Best for: Next-generation web images, maximum compression
- File size: Smallest
AVIF is the newest major format, offering even better compression than WebP. Browser support is growing rapidly (Chrome, Firefox, Safari 16.4+), but software compatibility is still limited. It's the best choice for web performance if your audience uses modern browsers.
SVG (Scalable Vector Graphics)
- Type: Vector (not raster)
- Transparency: Yes
- Best for: Logos, icons, illustrations, anything that needs to scale without quality loss
- File size: Very small for simple graphics; large for complex ones
SVG is fundamentally different from other formats on this list — it stores shapes as mathematical descriptions rather than pixels. It scales to any size without quality loss but is unsuitable for photographs.
GIF (Graphics Interchange Format)
- Compression: Lossless (limited to 256 colors)
- Transparency: Binary (on/off, no semi-transparency)
- Best for: Simple animations, memes
- File size: Small for simple images, large for animations
GIF is mainly used for short animations today. Its 256-color limit makes it unsuitable for photographs or complex graphics. For static images, PNG is almost always a better choice.
BMP (Bitmap)
- Compression: Usually none
- Transparency: No (standard BMP)
- Best for: Legacy software compatibility
- File size: Very large (uncompressed)
BMP is an old format that stores raw pixel data with no compression. There's rarely a reason to use BMP today — PNG does everything BMP does with much smaller file sizes.
TIFF (Tagged Image File Format)
- Compression: Lossless (optional)
- Transparency: Yes
- Best for: Professional photography, print workflows, archival
- File size: Very large
TIFF is the preferred format in professional photography and print production. It supports layers, multiple pages, and various color spaces. For web use, TIFF files are far too large.
Format Comparison Matrix
| Feature | PNG | JPG | WebP | AVIF | SVG | GIF | BMP | TIFF |
|---|---|---|---|---|---|---|---|---|
| Lossy compression | No | Yes | Both | Both | N/A | No | No | Optional |
| Lossless compression | Yes | No | Yes | Yes | N/A | Yes | No | Yes |
| Transparency | Yes | No | Yes | Yes | Yes | Binary | No | Yes |
| Animation | APNG | No | Yes | Yes | Yes | Yes | No | No |
| Max colors | 16M+ | 16M | 16M | 16M+ | Unlimited | 256 | 16M+ | 16M+ |
| Web support | Universal | Universal | Modern | Growing | Universal | Universal | Limited | None |
| Software support | Universal | Universal | Growing | Limited | Good | Universal | Universal | Good |
When to Use Each Format
| Situation | Best Format | Why |
|---|---|---|
| Photo for a website | WebP (or JPG fallback) | Smallest file, good quality |
| Logo or icon | SVG (or PNG) | Scales without quality loss |
| Screenshot with text | PNG | Lossless preserves text clarity |
| Image with transparent background | PNG or WebP | Full alpha channel support |
| Sending a photo by email | JPG | Universal compatibility, small size |
| Professional print file | TIFF or PNG | Lossless quality for print |
| Social media post | JPG or PNG | Universally accepted |
| Web performance (cutting edge) | AVIF | Best compression ratio |
| Short animation or meme | GIF or WebP | Animated format support |
How to Convert Between Formats with BestPNG
BestPNG offers dedicated converters for the most common format changes, all running in your browser with no upload required:
- PNG to JPG — reduce file size for photos
- JPG to PNG — preserve quality for editing
- WebP to PNG — universal compatibility
- PNG to SVG — vectorize graphics
- HEIC to JPG — open iPhone photos anywhere
- General format converter — convert between any supported formats
Batch Conversion
Need to convert many files at once? BestPNG's tools support batch processing. Drop multiple files and convert them all in one go — useful when migrating a website between formats or preparing a batch of images for a specific platform.
Common Conversion Scenarios
"My website images are too large"
Convert your PNGs to WebP or AVIF for significant size savings. If you need broad compatibility, WebP is the safer choice. For maximum compression on modern browsers, use AVIF.
"I can't open this file"
Convert uncommon formats (HEIC, WebP, AVIF) to PNG or JPG for universal compatibility. These two formats are supported by virtually every device and application.
"I need transparency but smaller file size"
Use WebP with lossless compression. It supports full alpha channel transparency at roughly 25-35% smaller file sizes than PNG.
"I need to print this image"
Use PNG or TIFF at the highest resolution available. Avoid JPG for print if possible — its lossy compression can cause visible artifacts, especially on text and sharp edges.
"I need this logo to scale to any size"
Convert it from PNG to SVG using BestPNG's vectorizer. SVG files are resolution-independent and scale without quality loss.
Frequently Asked Questions
Does converting between formats lose quality?
It depends on the formats involved. Converting between lossless formats (PNG to TIFF, for example) preserves quality perfectly. Converting from a lossless format to a lossy one (PNG to JPG) involves some quality loss. Converting from lossy to lossless (JPG to PNG) doesn't recover lost quality but prevents further degradation.
Which format has the smallest file size?
For photographs: AVIF is smallest, followed by WebP, then JPG. For simple graphics: SVG is smallest (as a vector), followed by WebP, then PNG. The actual size depends on the image content and compression settings.
Can I convert multiple images at once?
Yes. BestPNG's conversion tools support batch processing. Upload multiple files and convert them all simultaneously.
What's the best format for social media?
JPG or PNG. Most social platforms accept both and will re-compress the image on their end regardless. Use JPG for photos and PNG for graphics with text or transparency.
Should I use WebP or AVIF for my website?
WebP has broader browser support today and is the safer choice. AVIF offers better compression but is not supported by older browsers. Many sites serve AVIF to supported browsers and fall back to WebP or JPG for others.
Conclusion
There's no single "best" image format — the right choice depends on your specific needs. For everyday use, PNG and JPG cover most situations. For web performance, WebP and AVIF offer significant improvements. For scalable graphics, SVG is essential.
When you need to move between formats, BestPNG's free tools make it simple — no software to install, no sign-up required, and all processing happens in your browser.