0001 - Get Firefox.
0010 - Install Adblock.
0011 - When someone posts an uncut picture, right click on it and click adblock image. In the menu screen that pops up, click OK.
0100 - ???
0101 - Profit!
Mind you, if someone posts a shitload of pictures outside a cut, that's pretty rude unless it's in a community where all posts are expected to look like that. But! Adblock can help you there too, though you need to have some knowledge of the target image host's general directory structure (and probably regular expressions unless you can just use a wildcard).
Adblock with the filtersets lets you have a basically ad-free existence on the interwebs; it's not just for blocking those dumb sparkly graphics! It's also useful if you really hate somebody's icon (because it's ugly/NSFW/its subject matter offends you/the icon mocks you in your sleep/etc etc), instead of making angryfaces every time you see it, you can block it! You can also use Adblock to avoid other people's LJToys, statcounters, etc (that takes a little bit more work than three clicks, but it's still pretty easy).
But if you really can't be arsed with Firefox and/or Adblock, LiveJournal lets you alter your image placeholder preferences under display settings so that all uncut pictures will be displayed as an inline thumbnail. srsly u guys. no excuse wtf.
This has been a public service announcement brought to you in part by the words "you", "have", "control", "over", "what", "your", "computer", and "does".