I had the very same issue, I had 8 blank photos (kind of grey in color ) showing up in my picture folder, which would NOT delete.. I went into the drive for the picture folder, and they were showing as "PNG" picture files, and have no idea where they came from.. I had to do a complete reinstall of software to get rid of them.
Amazon Kindle for ebooks. I guess there are many apps which are being converted from android to bb10 witbout proper optimisation for the BlackBerry os. And these things are creating problems. PS: similar app is the ebay app which drains out your battery in 2 hours, weird but true. Suggestion is read the all the reviews in the BlackBerry worldapp before installing any new app