Iphoto problem

My old laptop, which was a HP, recently died, so I started using my aunt's old Macbook (which was still in good condition, of course.)
Before, when I uploaded photos onto the internet, they would be full size. Now, when I upload them from iphoto onto the internet, they are very small.
What can I do to change this?

There's a ton of things that could have happened to cause the images to upload small. Couple of questions:

What did you upload them to (specific site/location/service)?
Did you check the settings for uploading?

I'm not an iPhoto expert or regular user, but I'm almost 100% sure that there are controls for upload size hiding somewhere around there.

It sounds like you are uploading the thumbnail rather than the original picture, which suggests that perhaps the original pictures have been moved or didn't get transferred properly.

Can you describe, step-by-step, what you are doing in iPhoto to upload the pictures?