Hey thanks for the praise, I'm glad you get as much use out of it as myself.
Opera actually has a neat links feature built in, making it easy to grab all the images or whatever off of a page. Control + Shift + L is the default keyboard shortcut now I think, or you can just go to the Tools menu and pick Links. It shows you all the clickable things on a page.
To save all the images from a thread on 4chan, load the thread in question in its own window, bring the links window up, then put this into the search blank along the top:
/src/1
This filters only things coming from the /src/ directory on 4chan, and files starting with "1" immediately after it. If you don't put the 1, you'll get some duplicates in the list, I noticed. Images on 4chan should always start with a 1, because they save them based on the unix timestamp apparently, meaning it won't become a 2 until the year 2033! You might not need the 1 on other image boards, though, depending on what type of chan software they use.
But anyhow, then you can select however many images you want to save. Control-A will just select everything. Then you can right-click on'em, and either pick the Save As feature, or Save to Download Folder. If you pick the first one, I think it prompts you for every file. If you pick the other option, it saves them all with no prompting to whatever folder you have set in Opera as your download folder.
Hope that helps!