Could anyone tell me how I can transfer my photos downloaded direct to my iPad using camera connector kit to my camera, back to iPhoto library in my iMac.
AFAIK it should be a case of connecting iPad/computer, opening iTunes, select the device, click on the photo tab, check the sync box is checked and click sync, then open iPhoto to see your transferred images.
It is important as to what happens next as iPhoto will make a jpeg preview of your image, if you intend to edit the image further in say Photoshop you will need to make sure you are working with your original full size image file and not the iPhoto generated preview.
It may be possible to import the images directly via iPhoto, if I get my MBP running before another reply appears I will check it out.
The photos on the iPad that were imported via the Camera Connection Kit, should appear in iPhoto in exactly the same was they would if, for example, you inserted an SD card in a SD card reader on your iMac. There is no need to involve iTunes in the process.
Depending on your settings in iPhoto, iPhoto might open when you connect the iPad (just as it might if your inserted an SD card in a reader). Other wise you might have to start iPhoto.
This behavior is the same as many other photo Apps like Lightroom, Bridge and Aperture that all recognize the iPad as an import source - assuming, of course, that there are imported photos sitting on the iPad.