Why do 1 mW Laser Pointers appear more powerful than 5 mW, 10 mW and 15 mW power Laser Pointers

I've been looking on Ebay and I thought the more mW in the laser the more powerful, however, it appears in the images 1 mW laser beams are more visible and powerful than the higher mW lasers?

I would like a nice powerful laser where the beam is visible through the air.

Could someone explain please?

Just because the laser pointer has a higher mW, it doesn't mean that the beam will be more visible or powerful. With a lot of the cheaper laser pointers of the higher mW, it emits a lot of UV light making it so that up to 80% of the light generated is UV. You should look up reviews for good quality laser pointers before buying one. Also, many times, the pictures on Ebay are photo-shopped to look more vibrant, or they take a stock photo of the best laser of that kind and use that. Either way, looking up reviews of each one of the lasers should allow you to choose the better one and not waste your money.