You may refer to problems apparently mainly on Sony devices which cannot show jpeg pictures in progressive format.
Most pictures that you find on the internet are in the progressive format.
The progressive format is defined by the standard and should be supported by any device that knows how to display jpeg pictures.
Here is a thread, even though it is in German, refers to 2 English sites where you may find answers and tools to convert progressive format jpegs into baseline ones.
There is no way for MP3tag to tell the picture format. You would have to export them and check them there.