Hi everyone
Khanni’s suggestion is a great one.
A quick step by step:
1. Open your web browser (Internet Explorer/Google Chrome/Mozilla Firefox/Safari)
2. Go to http://picnik.com/app (wait for it to load)
3. Near the top left of the page, click the Upload button
4. Select photo you want to edit.
5. Click Resize (in the ‘Edit’ tab) and select put the dimensions as 800×600 (or 600×800 if the image is upright/portrait) and click OK
6. Select the ‘Save and Share’ tab, change the file name if you wish then click ‘Save Photo’
The photo is now ready to upload on MYA Space 
Hope that helps