I created a web app that helps the visitors edit images: formats conversion, dimension resizing, etc.
It's Convert Hub
The application is free and no registration is required. You can instantly use it after opening the website up in your browser. However, as I'm limited on server budget and image programs require large amount of RAM and disk I/O, the number of conversions per IP per day is restricted to a certain amount.
A free downloadable program that does the same things as the website app is offered. The free version has no usage limits whatsoever, you can use it as if you are using the website, WITHOUT the daily quota! However, if you need to convert a large number of images, you would want the batch version
which costs you $14.95
Hope you like it!