So I was thinking to model a car or motorcycle or basically any object that require a template image with front, side and top view. I tried to download those images from internet and rescaling them to same size but I just cant get it right. There is always one of those size doesn't match the other sides. Is there any other way to make it?
One way to do it is to scale the images first in an image editing program. Otherwise, you can scale them in the viewport>config>background menu. What I usually do is create a cube and scale it to match one view, and then use that as a reference to scale the BG reference in the other views. For example, you could load a side reference, create a cube and scale it so that matches the length and hight of the bike. Then load your top reference and scale the image so that the matches the length of your cube. Etc.