Alter some Images

I would like to have 2 vector pictures changed in order to makethem suitable for a T-shirt print. I would like to get a more vivid and highlighted picture that will look good on the front of a T-shirt. I need the picture to be in a vector format and to have 3 or 4 colours in total. The pictures will be screen-printed on T-shirts and I would like to have them look stylish and catchy! Also I want to incorporate into the designs the word - IMPROVE which would be written in a very stylish and simple font. This would be the name of the brand of the T-shirst. The colours of the T-shirts would most probably be white, grey, light blue or some other light colours - so the pictures should have colours that will look good on those [login to view URL] free to change the colours that are now present in the pictures.