A few more comments. I really like your image viewer. IMO it has potential to be a seperate App, if more image functions were put with it, if as with image browser app, QuickPic. I don't mean image effects. There is enough of that out there, but image or browser management tools. QP is the best browser IMO, but yours has some nice features, such as view actual size.
What I found odd though, is in the folder list of my main image folder, if I swipe to select a folder, or press Tools, there is ZERO functionality. None in tools, one via a long press on the selected folder, nothing anywhere else that I can find. Is this a bug? Selecting something should allow you to do something with the selection. There should be, IMO, global tools, under TOOLS, & folder specific tools via a long press, such as move, rename, copy, delete, send to, create shortcut & more. Please consider putting a zillion file management tools within "Tools" or rename Tools. Going to read "About", within tools makes no sense to me.
Also, folders "hidden" with QuickPic, are hidden from your app but not from other file explorer apps, such as Ghost. I thought this was a QP specific function, as it doesn't write a .nomedia file to the folder, but is a function within QP & not the folder? But maybe not.