title_body: pictures show twice in android app I received a 250MB epub file
  and unzipped it (with 7z) and just recompress it's jpeg's to ~50% size (not dimensions), keeping the same files names (with IfranView).
  
  I reziped to .epub and loaded it to my android tabs.
  Two apps open it but will display each picture twice. 
  Once without adjacent text and the second time with text 
  I do not have any special epub authoring software.
  
  Why it happened and can I correct it?
upvoted_answer: After so long I came back to this issue and found the solution.
  
  
  I open the epub in 7z (but not unzip) 
  I drag the image folder out and recompress it with Ifranview to my liking.
  Now I drag it back into the open 7z window to replace the old image folder
  close 7z, and now the epub is half size and opens correctly in any epub app,