You can always get IE to open a .jpg by pointing the browser directly to it (File, Open, Browse) or by keying the path into the address box.
Double-clicking while in Windows Explorer though will cause the 'associated' program to be used instead. In your case that's view32.exe which is QuickTime. The .jpg association was likely changed when you installed QT, either serruptiously or because you said 'yes' when it asked
Suggest you put the .jpg association back to IE. On the File Types list, select the JPEG entry, click edit then select the 'open' action in the box and click edit for that too. The 'Application used to perform action' box needs to be filled with the
full path for Iexplore. You can get that from the properties (right click the desktop icon) or by copying it from the BMP entry in File Types.