The blank problem was reported as fixed a couple of weeks ago and blanks have not been being downloaded since. If you delete the blanks that you have the photos will be downloaded next time the aircraft is picked up.
To aid you try this as advised by Niklas on 17th February
Open Explorer, go to the Photo folder (located: \Radarbox\Data\Photo), change view into details. Then sort on the Size column, select all photos that are 1 KB, then delete them.
The correct photo will then populate the next time.
Alan