Go into preferences in iPhoto and there's a little drop down menu that says 'When camera is connected...' change that to 'Do Nothing'.
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After my fresh install of Yosemite, iPhoto and iMovie were not installed for some reason (I thought they were there by default with an OS X install). I went to the App Store to see if I just needed to re-download them and it said I had to pay £13.99 a piece. Luckily I was able to pull them off of my Time Machine back up. Same happened with iWork which are apparently now meant to be free. I had to re-install Pages and MAS said I had to pay for it (again, I bought it the first time). Dunno what's going on with the MAS but it seems to forget your purchases!!
In short, you're welcome to remove iPhoto and iMovie from your Mac but don't guarantee you'll be able to get them back in the future.