How Many Thumbnails Should I Create and What Sizes Are Best?

Typically, services produce around 3 to 5 different thumbnail sizes to accommodate various scenarios. You'll want sizes like small (150-300px for profile pictures), medium (600-800px for mobile views), and large (1200-1600px for desktop). Instagram generates various sizes because it's essential to deliver the best fit according to the device and screen density. For mobile users, using a lighter version (like 640px) is ideal when a larger size isn't necessary. Don't forget to check out responsive images and the 'srcset' attribute so the browser can choose the best option for the current viewport. Also, consider using the WebP format for better compression.

Most modern platforms adopt a responsive design approach, so it's common to offer at least three sizes: small (around 150-300px), medium (600-800px), and a large or original size. Services like Twitter and Instagram choose these sizes based on a mix of UI requirements and standard breakpoints for different screen densities. For a simple demo, you might stick to generating a few standard widths such as 320w, 640w, and 1024w. Using the 'srcset' attribute in your HTML can help the browser select the best size for the user's device.

A good strategy is to create thumbnails on the fly and cache them. This lets you modify your design later without having to regenerate all thumbnails at once; you can just clear the cache for the images that need updating. Plus, you can remove cached thumbnails for rarely accessed images to conserve space.