Image Formats Explained: JPG, PNG, WebP, AVIF, GIF, BMP, TIFF and ICO

ImageConverter TeamApril 2, 20257 min read

Every image file you create, download, or share has a format — a set of rules that determines how pixel data is stored and compressed. Choosing the right format can mean the difference between a sharp, small file and a blurry, oversized one. This guide covers every major format supported by Free Image Converter.

JPG (JPEG)

File extension: `.jpg` or `.jpeg`

Compression: Lossy

Transparency: No

Animation: No

JPG is the most widely used image format in the world. It was designed for photographs and uses a mathematical technique called the Discrete Cosine Transform to reduce file size by selectively discarding information the eye is unlikely to notice.

JPG is ideal for photographs, camera images, and any image with many subtle colour gradations. It is not suitable for graphics with sharp edges, text, or flat colour areas — these produce visible artefacts (blocky patterns) when saved as JPG.

Best for: Photographs, hero images, product photos, social media images

Avoid for: Logos, screenshots, illustrations, images requiring transparency

PNG (Portable Network Graphics)

File extension: `.png`

Compression: Lossless

Transparency: Yes (full alpha channel)

Animation: No (use APNG for animated PNG, though support varies)

PNG was designed as an improved replacement for GIF and is the standard format for web graphics. Its lossless compression means the image is stored without any quality degradation, making it ideal for graphics that need to look exactly as created.

PNG files tend to be larger than JPG for photographic content — a photo saved as PNG can be 3–10× the size of the same image saved as JPG. For graphics with transparency or sharp edges, PNG is usually the better choice.

Best for: Logos, icons, illustrations, screenshots, graphics with transparency

Avoid for: Photographs intended for web use (use JPG or WebP instead)

WebP

File extension: `.webp`

Compression: Lossy or lossless (your choice)

Transparency: Yes

Animation: Yes

WebP is a modern format developed by Google that achieves better compression than both JPG and PNG. In lossy mode, WebP files are typically 25–35 % smaller than equivalent JPGs. In lossless mode, WebP files are typically 26 % smaller than equivalent PNGs.

WebP supports transparency (unlike JPG) and animation (unlike both JPG and PNG), making it a versatile all-around format for web use. Browser support is excellent — all major browsers have supported WebP since 2020.

Best for: Website images of all kinds — replaces both JPG and PNG for most web use cases

Avoid for: Very old browsers (IE11), print workflows, or applications that do not support WebP

AVIF

File extension: `.avif`

Compression: Lossy or lossless

Transparency: Yes

Animation: Yes

AVIF (AV1 Image File Format) is the newest major image format, derived from the AV1 video codec. It achieves compression that is 30–50 % better than JPG and noticeably better than WebP at the same visual quality.

AVIF is excellent for reducing page weight and improving loading speed. The main limitation is that it requires more processing power to encode and decode, which can be noticeable for very large images or on lower-powered devices. Browser support is good (Chrome, Firefox, Edge, Safari 16+) but not universal.

Best for: Images where the smallest file size is the priority, modern web pages

Avoid for: Applications or browsers without AVIF support, print workflows

GIF

File extension: `.gif`

Compression: Lossless (but limited to 256 colours)

Transparency: Yes (1-bit — pixels are either fully transparent or fully opaque)

Animation: Yes

GIF was one of the original web image formats, created in 1987. Its most distinctive feature is animation support. GIF is limited to 256 colours per frame, which makes it unsuitable for photographs — colour banding is visible in any image with smooth gradients.

For static images, GIF has been almost entirely replaced by PNG and WebP. For animations, GIF is still widely used despite being inefficient — a short animated GIF is often several megabytes, while the same animation as a looping WebP or short MP4 video would be a fraction of the size.

Best for: Simple animations, small graphics with few colours

Avoid for: Photographs, graphics with more than 256 colours, large animated content (use video formats instead)

BMP (Bitmap)

File extension: `.bmp`

Compression: Uncompressed (or very basic compression)

Transparency: Limited (32-bit BMP supports alpha)

Animation: No

BMP is one of the oldest image formats, originally developed for Windows. It stores pixel data with minimal or no compression, resulting in very large file sizes — a 1920 × 1080 px BMP is approximately 6 MB regardless of image content, compared to less than 1 MB for the same image as JPG.

BMP is still used in some Windows-specific software and professional imaging workflows where uncompressed data is required. For web use or general sharing, BMP is not recommended — use PNG for lossless images or JPG/WebP for photographs.

Best for: Windows applications requiring uncompressed data, certain legacy software workflows

Avoid for: Web use, sharing, email, or storage where file size matters

TIFF

File extension: `.tiff` or `.tif`

Compression: Lossless (or uncompressed)

Transparency: Yes

Animation: No

TIFF (Tagged Image File Format) is the professional standard for high-quality archival images, print production, and photography workflows. TIFF files can be very large — uncompressed TIFF stores every pixel at full bit depth — but they preserve image data with perfect fidelity.

TIFF is not suitable for web use (browsers do not display TIFF files natively) but is widely used in professional design, printing, and archiving. Photographers typically store their original edits as TIFF before exporting to smaller formats for distribution.

Best for: Print production, archival storage, professional photography workflows, scientific imaging

Avoid for: Web use, email, social media, any situation where file size matters

ICO

File extension: `.ico`

Compression: Stores PNG data internally

Transparency: Yes

Animation: No

ICO is the format used for browser favicons and Windows application icons. An ICO file can contain multiple image sizes in a single file — when you set a website favicon, you typically provide a 16×16, 32×32, and 48×48 version inside one `.ico` file.

ICO files are not used for general images. Their specific purpose is favicons and Windows icons.

Best for: Browser favicons, Windows application icons

Avoid for: Any general image use

Converting Between Formats

You can convert between all of these formats directly in your browser using Free Image Converter. Every conversion is processed locally on your device — no files are uploaded to any server.

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