Missing e-magazine covers.

[gaving]

Hi there. I used to use Calibre to load up e-magazines in the PDF format to send to my android tablet. The problem was that although the covers were showing in my Kindle app library, the text and pictures were all over the place thus making the magazine unreadable.
Now I use the Send To Kindle app without Calibre and although the text and pictures are fine, the cover does not show up in my Kindle library, only when I open the generic PDF logo which appears.
Has anyone else experienced this issue and is there a workaround?

Thanks,

Gavin.