It’s easy to browse the images on a Twitter account. Saving them is more of a challenge. Even the right-click menu may not have a "Save Image As" option.
DhIMG Twitter is a tiny free tool for Windows which avoids all these hassles by directly downloading the images (but not the videos) for a named account.
The program is a compact 72.7KB download, and unzips to a single portable executable which apparently runs on anything from Windows 98 up (we didn’t check).
After entering your target Twitter user name, you must choose the maximum number of images you’d like to download. We’re not sure why this can’t just default to "all of them", but there’s an option to download 1000 which for most accounts should be enough.
Click "Find Images…" once that’s done and dhIMG Twitter checks that your details are valid. If all is well, all you have to do is point the program at an export folder, click "Run" and it downloads everything in a few seconds.
The file names are cryptic, like "AyBsby9CAAAe0Mo.jpg", but that’s not the fault of dhIMG Twitter -- it’s the way they’re stored -- and if you just need to back up all your images then the program is a quick and hassle-free solution.