Please help with sprite sizes

Hello I'm going to make a 2d platformer game but don't know what sizes are typical for character and item sprites.......

Are sprites able to be scaled up or down after being placed inside construct 2 engine? Will doing this harm the game at all?

All info is greatly appreciated.

I'd think 32x32 or 32x64 would be fairly standard for your bounding boxes. You can scale things up ordain, but I recommend designing things bit larger than you need and scaling down than scaling them up, as image quality may degrade.

16,16 does it for me

There used to be a time when a sprite had to be a certain size but those days are over. Any multiple of 8 will usually look good so 8x8 16x16, 32x32 etc.

I use 32x32 for most of my games.

What does matter is how big the image is that you are loading into a sprite. Very large images will lose pixels and quality when reduced and vice versa so I try to stick with images around the same size as the sprite they will be used for.