Your image is the most important asset in your Responsive Display Ads. That’s why Google recommends to avoid:
Avoid using the following:
– Blurred images
– Skewed/distorted images
– Images that include a mirror image
– Washed out colors, inverted colors, excessive filters
– Images with borders
– Collage images
– Images with digital composite backgrounds
– Overlaid text on top of your images, which can be hard to read at smaller sizes.