How to view recovered (deleted earlier) images?
Recovering images from a previously formatted media usually means that the images are "carved" from the RAW data by detecting the image headers.

Images that are not stored as one data block (image is fragmented on file-system level) can not be fully recovered using the carving method because the information which blocks belong together was erased by formatting the media. You end up in having image files of the original size but from a certain point on the images just contain garbage data, not the image data. 

A good image recovery tool should detect those defect images and let you decide what to do with them. Looks like your software does not work this way and now you have broken images that can't be loaded fully - e.g. for generating the thumbnail. 

You may find software that is able to display the remaining parts of the original image, and save it to a new file. But this software has be be able to deal with defect image files and I don't know what Android apps could be used in such a case.