If you’re just looking to save a click, you can just go into your settings (click on your username in the top right and choose settings) and check the ‘auto-expand pictures’ box.

If you want to improve the overall experience, there are a number of options that I think will work with any browser you like. Personally, I use Firefox. I then add the Tampermonkey user scripting extension, with the LemmyTools and lemmy-keyboard-navigation scripts. Plus the ImagusMod extension which displays full images and videos on mouseovers.