Image File Formats

Why This Matters

In graphic design, choosing the wrong file format can tank your entire project—a pixelated logo on a billboard, a 50MB image crashing a website, or a flattened file that can't be edited. You're being tested on understanding the technical differences between formats and, more importantly, when to use each one. This means knowing concepts like lossy vs. lossless compression, raster vs. vector graphics, and color depth limitations.

Don't just memorize that PNG supports transparency—understand why that makes it the right choice for a logo overlay and the wrong choice for a photo gallery. The formats below are grouped by their primary function and underlying technology, so you can see the patterns that will help you make smart decisions in real design scenarios and answer exam questions with confidence.

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Raster Formats for Photography and Continuous Tone Images

These formats use a grid of pixels to represent images, making them ideal for photographs and complex imagery with smooth color gradients. The key tradeoff is always between file size and image quality.

JPEG (Joint Photographic Experts Group)

• Lossy compression—reduces file size by permanently discarding image data, which degrades quality with each save
• 24-bit color depth supports over 16 million colors, making it ideal for photographs and images with subtle gradients
• Best use case: web photos and digital photography where small file sizes matter more than perfect quality

TIFF (Tagged Image File Format)

• Professional print standard—preferred by photographers and publishers for archival-quality images
• Supports layers and channels, allowing non-destructive editing workflows in professional software
• Flexible compression options including both lossy and lossless, adapting to different project needs

RAW

• Unprocessed sensor data—retains every bit of information captured by the camera, unlike compressed formats
• Maximum editing flexibility allows adjustments to exposure, white balance, and color without quality loss
• Requires specialized software like Lightroom or Camera Raw for processing before use in design projects

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Raster Formats for Web Graphics and Transparency

These formats prioritize web performance and special features like transparency and animation. Understanding color limitations and compression types is essential here.

PNG (Portable Network Graphics)

• Lossless compression with transparency—preserves image quality while supporting 8-bit alpha channels for smooth edges
• 24-bit color plus transparency makes it superior to GIF for complex graphics with see-through areas
• Ideal for logos, icons, and text-heavy graphics where crisp edges matter more than file size

GIF (Graphics Interchange Format)

• Limited to 256 colors—uses indexed color, making it unsuitable for photographs but perfect for simple graphics
• Supports frame-based animation, which is why it dominates memes and simple web animations
• Lossless compression preserves quality but only within its restricted color palette

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Vector Formats for Scalable Graphics

Vector formats use mathematical paths rather than pixels, allowing infinite scaling without quality loss. This makes them essential for logos, icons, and any graphic that needs to work at multiple sizes.

SVG (Scalable Vector Graphics)

• XML-based vector format—can be edited with code and styled with CSS, making it uniquely web-friendly
• Infinite scalability means logos and icons stay crisp from favicon to billboard size
• Supports interactivity and animation through JavaScript, enabling dynamic web graphics

EPS (Encapsulated PostScript)

• Legacy print standard—widely compatible with professional printing workflows and older software
• Supports both vector and embedded raster elements, offering flexibility for complex designs
• Common for logo delivery because it works across different design applications and print vendors

AI (Adobe Illustrator)

• Native Illustrator format—preserves all layers, paths, effects, and editability for ongoing design work
• Full feature support for complex vector artwork including gradients, meshes, and live effects
• Limited compatibility outside Adobe ecosystem, so always export to other formats for sharing

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Working Files and Multi-Purpose Formats

These formats prioritize editability and cross-platform compatibility, serving as either working documents or final deliverables depending on the context.

PSD (Photoshop Document)

• Native Photoshop format—preserves all layers, masks, adjustment layers, and smart objects for non-destructive editing
• Essential for collaborative workflows where files need to be handed off for further editing
• Requires export for delivery—not suitable for final client files due to limited software compatibility

PDF (Portable Document Format)

• Universal compatibility—displays consistently across all devices and operating systems without design software
• Supports both vector and raster content, making it versatile for everything from logos to photo books
• Print-ready standard commonly used for portfolios, presentations, and sending files to commercial printers

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Quick Reference Table

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Self-Check Questions

1. Which two formats both support transparency but differ significantly in color depth capability? What makes one better for photographs and the other better for simple graphics?

2. A client needs a logo that will appear on business cards, billboards, and their website. Which format category should you work in, and which specific formats would you deliver for print vs. web?

3. Compare and contrast JPEG and PNG: What type of compression does each use, and how does this affect your choice when exporting a photograph versus a logo with text?

4. You're preparing images for a high-end magazine print job. Rank JPEG, TIFF, and PNG in order of preference and explain the reasoning behind your top choice.

5. A designer sends you a PSD file and an AI file for the same project. Without opening them, what can you infer about the type of content in each file and how they were likely created?