@mokane99 Most newer, conventional RapidWeaver themes support dragged and dropped banner images. You can either set the same image to display on all pages, or vary the images shown between different pages.
Older or more specialist themes may not support dragged and dropped banner images. RapidWeaver will tell you if the theme does not support dragged and dropped banner images. In which case, you will need to find the documentation for the theme or ask the developer for help. Themes need to be updated to support dragged and dropped banner images.
For any other unexpected behaviour, bugs or general weirdness in RapidWeaver 8, then your best option is to forward all the details onto Realmac to take a closer look at.
It is very unusual nowadays to find oneself needing to open the guts of a theme to manually swap-out images. And with many themes supporting automatic updates, you’d probably be advised to leave non-duplicated themes well alone. If you need to edit a theme, always duplicate it and rename it properly from within RapidWeaver.
Tools like RWMultiTool have not been updated for a while and others like RWThemeMiner have been discontinued altogether. Simply because there are newer and easier ways to get custom banners into themes. I think this is a trend that may continue.
It is possible to change themes on a page-by-page basis if required. But this is a very rare occurrence. Most people tend to stick with using the same theme for a whole project. It is easy enough to customise certain variables like the banner area or hiding a sidebar etc. on individual pages.
I see no “problems” with the way newer themes handle banner images and it seems the 3 people who ‘liked’ my last post would agree. I feel you might perhaps be making this process far more complicated than it needs to be, which I why I’m suggesting you apply the brakes for a moment and carefully research the options you have for editing theme banners in RapidWeaver 8. Newer and updated themes make the process remarkably quick, safe and simple.