A lot of text books that I own are in the PDF format. Since PDF doesn't really draw well in Kindle, I follow this procedure
PDF -> word (via manual copy pasting) -> Mobi
to convert them to Mobi format for seamless reading.
I come across a lot of images in these PDFs and I use the traditional way of copying images
CTRL + Prt Scr -> Paste in Paint -> Crop -> Copy -> Paste in docx
which tends to be very cumbersome.
I am looking for a software that would require only a few clicks (or button combinations) to do capture -> crop -> copy -> paste of the images.