It sounds like the file extension (*.dll) is for your Canon program. When you open the picture on your computer click "Save as" under the file tab. It should give you the option of changing the file name and under that there should be a box for the file type. Change that to a .jpg or any of those listed in your post and save it. Then you should be good to go for uploading.
SS
"To be glad of life because it gives you a chance to love and to work and to play and to look up at the stars. To be satisfied with your possessions but not content with yourself until you have made the best of them." -Henry Van Dyke
