I want to use my own image for interstitial ads in admob, what is the best size for the image (width x height) so it looks good across device?
I know interstitial ads is full screen, but I worry if it will looks bad if loaded in bigger screen device.
Also what is the appropriate image format for the ads? Is PNG enough?
Refer this Link.
There is no need to define a separate ad unit for landscape mode. You can simply add the landscape size (e.g. 480x320 for smartphones) to line items targeting the interstitial ad unit and include a creative with the landscape size in addition to the regular portrait size.
Phones: 320x480 (portrait), 480x320 (landscape)
Tablets: 768x1024 (portrait), 1024x768 (landscape)