Understanding Pixels, DPI, and Print Sizes
Image dimensions are measured in pixels (picture elements), the individual dots that make up digital images. A 1920x1080 image contains about 2 million pixels arranged in a grid 1920 wide and 1080 tall.
DPI (dots per inch) only matters for printing. A 3000x2000 pixel image printed at 300 DPI produces a 10x6.67 inch print. The same image at 72 DPI would print at 41x27 inches but look pixelated up close. For screens, pixel dimensions matter more than DPI.
Resizing for Web vs Print vs Social Media
Web images should match their display size. A hero image displayed at 1200 pixels wide needs to be 1200 pixels (or 2400 for retina displays). Larger files waste bandwidth without visible benefit.
Social media platforms have specific size requirements: Instagram posts work well at 1080x1080, Facebook covers need 820x312, LinkedIn banners use 1584x396. Meeting these dimensions prevents cropping surprises.
Maintaining Aspect Ratio to Avoid Distortion
Aspect ratio is the proportional relationship between width and height. A 4:3 photo stretched to 16:9 without cropping will appear distorted—people look wider, circles become ovals.
FormatWiz locks aspect ratio by default. When you change width, height adjusts automatically to maintain proportions. Unlock this only when you specifically need non-proportional resizing or are matching exact dimensions that differ from the original ratio.
Private Resizing Without Uploads
FormatWiz resizes images entirely in your browser using HTML5 canvas APIs. Your photos never upload to external servers, making this safe for personal photos, confidential documents, or any images you prefer to keep private.
Processing speed depends on your device's capabilities, but modern browsers handle even large images efficiently. Results are comparable to desktop software like Photoshop.