Photo frame apps and adware

[Moltres_rider]

I've tested out dozens of photo frame apps, mostly love ones and found out that 99% of them have push ads to your notifications bar (only 1 I've tried didn't)... so, why does all the photo frames apps in Google Play have push ads in them???

 

[Adamsberg]

I guess because all apps of this kind have the purpose to show a photo in a frame ... and there is no room for to place a standard ad without spoiling the design.