If you need to do image resizing, or convert your image or water mark your photos you can use this useful site for this: http://diozo.com/
Looks good & useful to know! Photoshop will give you more options though, without having to upload anything - but it's expensive!
Very useful! Ive got a large amount of logos and mascots i want to display on my site but need them watermarking! Thanks!! ***EDIT*** Ah looking at the website it is actually quite expensive!