Excellent!
The picture size is fine, but if you were posting a few of them, you'd end up with an immense post and sometimes you can add a picture and it's just huge. You can adjust the size by clicking 'modify post' once it's up on here. You'll then see that where you added the photo into the text, that there are now numerical values for the picture size, just change them to whatever size you want.
Once you get used to how this thing works, then you can get really clever and add links to the photo to direct to the gallery it's hosted on, or direct to your blog etc. Feel free to PM me if you need help or anything, it's what they pay me for, or at least it would be if they actually paid me.