I’m using PocketBook InkPad X and I sent an article  to my device. While overall formatting was good, the images weren’t centered horizontally and protruded past the right screen boundary, so that the rightmost part of the images were not visible.
I don’t know whether it is a PocketBook issue or a PushToKindle one. If you think that’s PocketBook’s fault, I’ll reach out to their support.
I also tried to download this article in Mobi format as a workaround, and the images were fine, but the rest of formatting was bad, especially quotes from another articles.