The 3 Computer Monitor Prints
It looks like you just took random images off google search and put them in blockland. You have to make the sides of those prints transparent so the edges could be the same color as the brick.
Recolor the brick?
You don't understand. You know the default computer screen print? You can recolor the 'edge'. (last i saw i think) People might want a white computer. Just make it transparent, it's not that hard. Unless you're using MS paint.
With Paint.NET it's just a simple thing of using the wand tool on a small percentage and just cutting out the small odd pixles using the selection box tool. You can do it, just try.
I find it really difficult to make the edge transparent while keeping the DELL logo and the button controls.
There we go! That's how you do it. Good job. You're improving.