You can upload virtually unlimited images and albums as long as you use the default upload option "High Resolution files - Faster upload".

Using this option you can upload virtually unlimited images. This option will resize images to 3500 pixels. These files can print up to poster-size canvases and are more than sufficient for web use. We recommend to upload a test album for you and see it yourself.

If you wish to upload your albums using the "original files" option then you now have 100GB space instead of 10GB. There is no extra charge for this upgrade. If you need more space for your account, you can either remove old albums or purchase additional storage at $0.10 per GB.