I'm not sure with this one. Since, I'm still newb in rendering images. But, I'll share a little tips in here ^^
1. First, open the image that you want to make the render. I suggest to choose image with blank white background (BG) because it's easier. Example...
I found these kind of images in my favorite site, 4Gamer.
2. Under the image layer, create a colored BG with the "Rectangle Tool". I usually use color which isnt in the original image to make sure I dont erase the one that I want to render Lolz or you can say it's for the contrast part. For those 2 images above, you can use green, red, etc.
3. For all renders that I made so far, I was using the "Eraser Tool"
There are other methods to render images, ie using layer mask or "Lasso Tool". I've tried it, and it's so difficult to find the best setting. Or maybe I read the wrong tuto Lol. You guys can share it in here, if you are using those methods ^^
For the "Eraser Tool", I usually use the Hard Round type, 10-200 px for the spacious BG. It depends your image size, the larger the image size, you will need bigger eraser to make it fast.
If you are almost near the render object, use 3-5 px
And hard edges (images above), use 1 or 2 px with 80% opacity..
Well, that's how I make a render. Hope it helps..
Ahh! For the layer mask method, I found a good one in here. I'm trying it to my Ada Wong render now he3