Would like to find a useful picture processing software (with details)

To be a slide, heard the latest OFFICE2007's slide in the new picture on the effect of such and such, but I do not have the latest version of OFFICE, did not dare to use pirated computer effects …afraid to ask Is there a better image-processing software? Free, do not have a virus!

to office in the end you still have to picture processing software? `image-processing software do not meet your needs only photoshop A.Picture deal with
PHOTOSHOP, then it should be the most powerful image processing software, the software you use photoshop ah! You do not have the money to buy pirated ah