When I create desktop icons for Apps, some have TINY pictures. Example:
Click image for larger version. 

Name:	2016_09_05_17_13_041.png 
Views:	12 
Size:	7.1 KB 
ID:	99988
Same procedure to create the desktop icons, but different results. Another example:
Click image for larger version. 

Name:	2016_09_05_17_15_272.png 
Views:	12 
Size:	18.7 KB 
ID:	99989
Procedure: click-drag-drop program icon from All Apps to desktop.

Note: screen resolution is 1366x768 (Recommended)