Hey Kafar and thank you so much for the feedback, as for the background that was the highest quality I could find, I think that the pixel look of it (the game) itself doesn't make things better so for this I can get away with it haha. As for the front logo, yea I see its a little low in quality now, my bad... I will remember next time.
And yes, I have been experimenting with .PNG and the covers come out at around 7 to 8mb which is good as the max file upload is 20mb on here. I will also do this next time
I was actually working on a lot of my template which I am happy with, your design with the steam theme kind of inspired me for mine though I didn't want to directly copy it, though honestly before your reply I was debating or not to add the blue line just above my background on the bottom layer as its like that on the bottom of the front steam logo banner too. It kind of gives it that break feeling.
I am using Photoshop, and thank you for your welcoming, I am sure going to make many, I am a collector of game cases back in the day and kind of miss having my selfs stacked with games, though I have almost 600 games on steam so I have a looooooong way to go lol.
Edit: Just finished my 2nd one, this one is the highest quality I could get, and just under 8mb .PNG
https://i.imgur.com/KRFEEKN.jpg