It's great to hear some stoke here! Very cool about your daughter. We just discovered that ours is a mermaid.
Not trying to talk down, but the first thing you need to do is to get the pictures the right size. If you've got a nice camera, you're gonna need to resize them in Microsoft Photo Editor or Paint. If you've got Office installed, you've probably got Photo Editor. Look around in the Programs menu, maybe under Microsoft Office Tools. If it's not there, do a search for photoed.exe and then launch it.
Once in, you can browse to and open your image. Then select Image and then Resize. Change the Units to pixels, make sure Allow Distortion is unchecked, and then change the size of the picture to some figure like 1000 pixels wide (or less). 800 is good, too. Make sure when you save the file, you Save As a jpeg, and then select the Other Options during the save to set the image to like 100% resolution (at first).
MS Paint is available on all Windows machines, but you'll have to resize using the Stretch/Skew tool. You'll have to stretch the size by some percentage in one direction and press okay, then the same percentage in the other direction and press okay. You'll have need to select Save As jpeg option as well.
Now you've got a picture that's the right size on the screen, so you'll have to also make sure it's not too large in terms of file size. Not sure what the magic number is, but it's good to keep them under 100K. After you've resized them, look in Windows Explorer to their folder and see what the file sizes list at (I don't trust the numbers that Photo Ed or Paint display).
If they're over 100K, you'll open them back up in Photoed and then select Save As and then change the other options, resolution to 95% or 90% or whatever it takes to thin the file down to 100K. Again, for file size, only trust what Explorer reports.
Finally, go to WakeWorld and select Upload Attachment. Enter in a 'name' if you like (can be whatever you like, as it has nothing to do with tthe filename.) Then, you'll browse to your freshly shrunken and thinned photos on your hard drive and will press upload. After a few seconds, you'll either get a 'Image Uploaded' or some error. Enter your text in the Post box and when ready to post, select Preview/Post Message.
You can post many pictures in the same post if you like. Biggest hassle is just resizing the photos in the first place.