Image Format Guide

A comprehensive reference for all image formats supported by theimgapp. Learn when to use each format, their strengths and limitations, and how to choose the right one for your use case.

Quick Reference Table

JPEG (JPG)

JPEG (Joint Photographic Experts Group) is the most widely used image format for photographs. It uses lossy compression to achieve small file sizes at the cost of some quality loss.

Key Characteristics

• Compression: Lossy — quality degrades each time the image is re-saved
• Color depth: 24-bit (16.7 million colors)
• Transparency: Not supported
• File extension: .jpg, .jpeg
• MIME type: image/jpeg
• Typical compression: 10:1 at quality 80-85% (imperceptible loss)

When to Use JPEG

• Photographs and complex natural images
• Web page hero images and backgrounds
• Social media post images
• Ecommerce product photography
• Any image where file size is more important than pixel-perfect quality

When NOT to Use JPEG

• Images requiring transparency (use PNG or WebP)
• Text-heavy images, screenshots (compression artifacts around edges)
• Logos and icons (use SVG or PNG)
• Images you plan to edit multiple times (use PNG as working format)

Convert with theimgapp: Format Converter | Compress JPEG | Progressive JPEG

PNG

PNG (Portable Network Graphics) is a lossless raster format with full alpha transparency support. It preserves every pixel perfectly, making it ideal for graphics, screenshots, and images requiring transparency.

Key Characteristics

• Compression: Lossless — pixel-perfect output on every save
• Color depth: Up to 48-bit + 16-bit alpha
• Transparency: Full alpha channel (256 levels per pixel)
• File extension: .png
• MIME type: image/png
• Typical size: 5-10x larger than equivalent JPEG for photos

When to Use PNG

• Graphics, logos, and icons requiring transparency
• Screenshots and UI mockups (sharp text edges)
• Images with few colors (PNG can be smaller than JPEG)
• Technical diagrams and charts
• Working/archival copies you'll edit repeatedly

Convert with theimgapp: Format Converter | Quantize Colors | Lossless Optimize

WebP

WebP is Google's modern image format offering superior compression to both JPEG and PNG. It supports lossy, lossless, transparency, and animation — making it the most versatile web format.

Key Characteristics

• Compression: Both lossy and lossless
• Size vs JPEG: 30% smaller at equivalent visual quality
• Size vs PNG: 26% smaller (lossless)
• Transparency: Full alpha (both lossy and lossless)
• Animation: Supported (replaces GIF)
• Browser support: All modern browsers (Chrome, Firefox, Safari 14+, Edge)
• File extension: .webp
• MIME type: image/webp

When to Use WebP

• All web images (photos, graphics, transparent elements)
• When you need smaller files than JPEG/PNG with same quality
• Animated content (more efficient than GIF)
• Transparent images where PNG is too large

Convert with theimgapp: Format Converter | Compress Images

AVIF

AVIF (AV1 Image File Format) is the newest web image format, based on the AV1 video codec. It offers the best compression available — 50% smaller than JPEG and 20% smaller than WebP.

Key Characteristics

• Compression: Both lossy and lossless
• Size vs JPEG: ~50% smaller at equivalent quality
• Size vs WebP: ~20% smaller
• HDR: Supports 10-bit and 12-bit color depth
• Transparency: Full alpha channel
• Encoding speed: Slow (10-20x slower than WebP)
• Browser support: Chrome, Firefox, Safari 16.4+ (~93%)
• File extension: .avif
• MIME type: image/avif

When to Use AVIF

• When smallest possible file size is critical
• Photo-heavy websites with bandwidth concerns
• HDR content for modern displays
• When you can pre-encode (slow encoding is acceptable)
• As primary format with WebP/JPEG fallback using <picture> element

Convert with theimgapp: Format Converter

HEIC / HEIF

HEIC (High Efficiency Image Container) is Apple's image format using the HEIF standard with HEVC compression. iPhones use it by default since iOS 11 (2017) for 50% space savings over JPEG.

Key Characteristics

• Compression: Lossy (HEVC codec)
• Size vs JPEG: ~50% smaller at equivalent quality
• Color depth: Up to 16-bit
• Transparency: Not commonly used
• Platform: Apple ecosystem (iOS, macOS)
• Browser support: Safari only
• File extension: .heic, .heif
• MIME type: image/heic, image/heif

The HEIC Problem

Windows, most web platforms, and many applications don't support HEIC natively. If you need to share iPhone photos or upload them to non-Apple services, converting to JPEG is the simplest solution.

Convert with theimgapp: HEIC to JPG Converter

SVG

SVG (Scalable Vector Graphics) is an XML-based vector image format. Unlike raster formats, SVG images scale to any size without quality loss because they define shapes mathematically.

Key Characteristics

• Type: Vector (resolution-independent)
• Scalability: Infinite — no pixelation at any size
• Transparency: Full support
• Animation: CSS and SMIL animation
• Editability: Text-based (XML), editable in code
• Browser support: Universal
• File extension: .svg
• MIME type: image/svg+xml

When to Use SVG

• Logos and brand marks
• Icons and UI elements
• Illustrations and infographics
• Any graphic that needs to scale (responsive design)
• Animated icons and interactive graphics

Convert with theimgapp: SVG to PNG

GIF

GIF (Graphics Interchange Format) supports animation and basic transparency. Limited to 256 colors, it's inefficient for modern use — WebP and MP4 are better alternatives.

Key Characteristics

• Colors: Maximum 256 (8-bit palette)
• Transparency: 1-bit (fully transparent or opaque, no semi-transparency)
• Animation: Yes (the original web animation format)
• File size: Very large for animations (GIF is highly inefficient)
• Browser support: Universal

Better Alternatives to GIF

• MP4 video: 80-95% smaller than equivalent GIF (Convert GIF to MP4)
• WebP animation: Much smaller with full color support
• AVIF sequence: Best compression for animations

How to Choose the Right Format

Decision Flow

1. Is it a vector graphic? → Use SVG
2. Does it need animation? → Use MP4 (from GIF) or WebP animation
3. Does it need transparency? → Use WebP (smallest) or PNG (most compatible)
4. Is it for the web? → Use AVIF (smallest) with WebP fallback
5. Is it a photograph? → Use JPEG (universal) or WebP (smaller)
6. Is it for print? → Use TIFF or high-quality PNG

Format Size Comparison (typical photograph)

Convert Between Formats with theimgapp

All format conversions happen in your browser — no files uploaded to any server. Free, no signup, batch processing supported.