JPEG (Joint Photographic Experts Group) is the most widely used image file format in photography and on the web. It uses lossy compression to reduce file sizes dramatically while maintaining acceptable visual quality for most purposes. Nearly every digital camera, phone, computer, and web browser can create, display, and edit JPEG files, making it the universal standard for sharing photographs.
How JPEG Compression Works
JPEG compression analyzes an image in small blocks and discards visual information that the human eye is least likely to notice. Fine color variations, subtle tonal gradients, and high-frequency detail are simplified or removed. The result is a much smaller file that looks nearly identical to the original at reasonable viewing sizes. Higher compression ratios produce smaller files but introduce more visible artifacts, particularly around sharp edges, text, and areas of high contrast.
Quality Settings
Most cameras and editing software let you choose a JPEG quality level, typically on a scale from 1-100 or as labels like Fine, Normal, and Basic. Higher quality settings preserve more detail and produce larger files. Lower quality settings create smaller files with more visible compression artifacts. For photography, quality settings of 80-95 provide an excellent balance between file size and visual quality. Below 70, artifacts become noticeable, especially in smooth gradients like blue skies where banding may appear.
JPEG vs. RAW
When a camera saves a JPEG, it applies all processing internally: white balance, color profiles, sharpening, noise reduction, and compression. These changes are baked into the file permanently. A RAW file preserves all original sensor data at full bit depth, giving you complete control in post-processing. The trade-off is that RAW files are three to five times larger and require dedicated editing software. For situations where speed, convenience, and immediate sharing matter more than editing flexibility, JPEG is the practical choice.
Avoiding Quality Loss
Because JPEG compression is lossy, each time you open, edit, and re-save a JPEG file, additional quality is lost. This is called generation loss. For editing workflows, either start from a RAW file and export to JPEG only as a final step, or save working copies in a lossless format like TIFF or PNG and convert to JPEG only for delivery and sharing. This preserves maximum quality throughout your editing process.