I found this from the cannon tech support people. it doesnt really tell you "ware" you pictures are but this said below may help.......
"Scans can be performed using your MP Navigator program. This program should be installed on your computer. The program has the ability to scan and send images to some email clients. If your email program is not able to be selected in the MP Navigator, you can save the scan to your computer using the software. Then use the 'attach' option in your email client to manually attach images or files from your computer."
Its saying you can at least see your photos with this "MP Navigator" program. meaning it should show the directory ware the photos are stored.
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They could be hidden in the "app data" folder hiding in your documents folder. if its in their then it would be in a folder called somthing like "cannon" in the "app data" folder. I dont know what windows you have so if you want to look for this folder... click START, RUN. type %appdata% hit enter. it'll pop up.
Also if you know the file extension of the photos like .jpg, .png or .bmp. you can use your search to find these. say for example the photos are ".png" what you need to do especially if you forgot the names of these files... type *.png
the star* means all files of the file extension ".png" will found and located. sorry for the long answer.
***Just wanted to add-
".jpg" and ".jpeg" are old file compression formats and ".png" its the new gold standard for small, high quality images.