You’d wonder what’s happening to Apple’s software quality control, when you spent hours trying to figure out what’s wrong trying to import photos from your iPhone, SD card to the Mac. You are not alone as there are many reports of Mac users encountering extremely slow import of photos using Image Capture, Aperture or Photos app.
The issue happens when you’re running the latest and fifth release of OS X Yosemite 10.10.4. Turns out that there is a workaround. Before plugging in your iPhone or SD card, turn off the Wi-Fi on your Mac and your iPhone. You should see the import speed back to normal. Hopefully Apple is fixing this in the next Yosemite release.
Update: It appears that the recently released OS X Yosemite 10.10.5 has fixed this issue.