I spend a lot of time looking at screen mock-ups through my browser, and I’m always annoyed when Firefox decides to resize the image because it doesn’t exactly fit in my viewport. This forces me to click on every image to expand it to the full size. Turns out, you can switch this default.

1. Type “about:config” into the browser location
2. Type “image” into the filter field
3. Double-click on “browser.enable_automatic_image_resizing” to turn the feature off

You can still have Firefox resize an image to big for your browser with a click, but it just doesn’t do it by default. Much better.