Problem: Transparent GIF and PNG inserted images do not display, export, or print as transparent
The transparent background of inserted GIF and PNG images is not maintained in ArcMap Layout and/or do not export or print transparently.
Transparent backgrounds are not supported by ArcMap, because it requires meta-processing of transparency. This is not supported between layout elements.
Solution or Workaround
Use one of the following two solutions to solve this issue.
It is highly recommended to download and use ArcGIS Pro to perform all printing and exporting functions.
ArcGIS Pro is not limited by the graphical device interface (GDI) limitations which exist in ArcMap. Transparency is no longer converted to raster formats, and thus ArcGIS Pro supports transparency in layout elements.
Additionally, Web Open Font Format (WOFF) support in SVG allows for better text embedding.
Use a pure vector EMF graphic instead. See the links in the Related Information section below for more information.