how to determine photo pixil size
How do I determine the pixil size of a photo I took in iphone? and how do I turn it into 350 x 350 pixil jpeg?
MacBook Pro, OS X Yosemite (10.10.5)
In Photos for Mac (the app you posted about) right click on the photos and get info - that will give the pixel dimensions
to change them to 350x350 edit the photos in Photos for Mac and crop to any square (1x1 or 1000x1000 - any square) the export the photo (file menu ==> export) with a maximum dimension of 350 (if the size options are not visible in the export window click on the v to the right of JPEG to show them)
LN