Horrible image compression when exporting from Premiere Pro

Hi everyone.

I’m a Premiere Pro noob and I know that this question/issue has been raised many times before, but I've tried everything I can find in every forum and post and still haven't fixed the issue I'm having.

I have several video files that are 1280x720, that I've placed in a project sequence, which is also set to be 1280x720. I also have some images in the sequence. They are PNGs (although I have also tried JPG with the same results), and they are of the same resolution as my video (1280x720). There are also some sound files (mp3s).

I can't find a way of exporting my video without the image files in it being horribly compressed (at least, I assume it's compression making them look awful). The image below shows a screengrab of what the image looks like when the exported video is playing (top left). Immediately below this is the image I imported in to PP and added to the sequence. For context, the logo at the righthand side of the image below is a screengrab of a video element of the exported video, just to show that this compression isn’t happening to video elements – only images. The screengrab was taken from playback through the ‘films and tv’ app in Windows, but I’ve also played it through my TV with the exact same results. Given that the rest of the video is fine, I’m confident it isn’t a playback/player issue – it’s either something in the export settings or in my actual project set-up.

Here’s what I’ve tried to fix it:

• Pretty much every combination of settings under the export menu, including different file formats.
• Exporting the video without re-scaling the image first, and also reducing the scale and then exporting - I get the same result with each.
• Creating a new image from text created within CC, using the 'title' function - same result on export.
• Creating a new sequence with the field setting as 'progressive' and pasting the images in to this
• Undertaking 'render and replace' on the image before exporting
• enabling 'full' playback resolution in the program monitor prior to exporting (seems a weird one, but somebody suggested it somewhere)

Please, please, please can someone help – I’ve spent more time trying to resolve this one issue than I have trying to teach myself PP creating the entire video.

Yours in hope and desperation, Mark