Hi people! So now I got confident with my iliad I need to fill it with content

As I want to use it for academic purposes there are 3 major sources of data. PDFs you can download, Books you scan yourself, and readers you get already in scanned format.
So I now scanned through a book, and also for the latest course, they offered me directly the PDFs they scanned to use for the iliad they otherwise normally print their course lecture they sell for copycosts to the students.
However the problem is formatting. When I for example scanned the book, I put it front face down on the scanner, 2 sites fitting on an A4 page for one scan. Now I got all the .pngs (I used OmniPage to scan and export it), but I need to split the images, and rotate them.
So is there any tool, that can comfortable clip/rotate a whole batch of images? Ideally one should be able to specify settings for one page, since the clipping region differs from book to book, or scanned paper, but usually stays the same through the whole title.
Right now I got my first 10 page article readable on the iliad, without zooming/panning woes. I exported the PDF I got into a set of png's. Used Gimp to open all of them. Copy/pasted the pages to new images, rotated them, saved them. Imported them back into OmniPage, printed it to pdf. And downloaded it on the Iliad. Whola!
This was do-able with a 10 page article and took a hour! (also with figuring some things out). I could have actually read the article in this time on printed paper instead
But well, who knows of any tool, or knows how to such tasks. I guess it is something many people will encounter when using their iliad....