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pryce56

macrumors newbie
Original poster
Sep 19, 2016
5
0
Canada
This is a picture of what I get when I open a photo in preview. I cannot find a post anywhere that shows this kind of problem. Does it look like my graphics card is going. I don't have any problem when using lightroom or PS CC

Screen Shot 2016-09-19 at 2.14.36 PM.png
 
Looks like some sort of screen saver, since the whole screen is involved and the menu behind the pattern is blurred. Can you check that that's off?
 
I am sure that is not it. I had opened the file again in preview to resize it for this thread. Here it is without.
Screen Shot 2016-09-19 at 4.09.46 PM.png
 
I am sure that is not it. I had opened the file again in preview to resize it for this thread. Here it is without.View attachment 655076

Ah, that's why it was so confusing. It could be the GPU hardware-image-compression failing (assuming Preview uses that), but I haven't seen this before either. Could you post just a piece of the image, unscaled so we can see the true-pixel detail? Use PS instead of Preview to do the cropping, of course.
 
MC6800 Thank you for your help. Is this what you were looking for? if not could you tell me how to do it. I have reinstalled El Capitan (not a clean install) as per Apple people's instructions which did not help. I am very puzzled, Bonnie

Screen Shot 2016-09-19 at 10.22.48 PM copy.jpg
 
MC6800 Thank you for your help. Is this what you were looking for? if not could you tell me how to do it. I have reinstalled El Capitan (not a clean install) as per Apple people's instructions which did not help. I am very puzzled, Bonnie

View attachment 655219

I think what you posted is right. If we're seeing actual 1-to-1 pixels, then those colored-star patterns are what you see on your screen. Very odd. I can't think of a failure mode that would do that-- it looks like smoothing after scattered memory failures, yet the image it's on hasn't been smoothed that much if at all.

Is this a MacBook Pro from 2011-2013? Those are known to have GPU problems (I've had mine repaired).
 
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OP:
Why don't you tell us a little about the MacBook you have?
Year of manufacture?
Screen size?
 
Hi Fishrrman. I am on a 2012 iMac up to date with OS X El Capitan, 3.4 GHz Intel Core i7 with 16 GB 1600 MHz DDR3 Memory. Graphics: NVIDIA GeForce GTX 680MX 2048 MB. 27" Screen. It has worked fine until the last 3 days. I have noticed however if I zoom in and out on the image opened in preview that at some zooms the weird pixelation disappears and then at another comes back again. Cannot figure out if this is a hardware or software problem. Have not installed anything new in the past 2 weeks. Any thoughts?

I run a parallels windows desktop but without much on it. When I open the image in Windows Picture Viewer the image is fine.
 
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