I opened Image Capture just to test. I had not had this problem in the past.
I connected my iPhone 4S and it showed 0 pictures...
Fortunately, I found an easy solution, which I hope will help you too.
I just deleted Image Capture's preferences.
To do this: option-click the Go menu in the Finder and choose Library (this folder is usually hidden).
Inside, open the Preferences folder, and locate all files related to Image Capture.
I had those:
com.apple.Image_Capture.plist
com.apple.ImageCapture2.DFDCEEF9-F610-554C-8292-B8434B57B2F5.plist
com.apple.ImageCaptureExtension2.59DD19E9-F546-5C70-9942-A5A367625F67.plist
com.apple.ImageCaptureExtension2.DFDCEEF9-F610-554C-8292-B8434B57B2F5.plist
These long series of letters and numbers will vary.
I just put them in a folder in my Desktop (just in case), and started Image Capture again. It immediately recognized all the images in my iPhone.
Now I can trash those preference files.