Question Corrupt/Grey(Gray) images

I have the same problem with images. Dear Kunena developers, you now I am not alone in my trouble. Help us please to solve it. You says it is not Kunena issue, but php. It seems you know PHP programming? )) What should I do about PHP to force my forum work correctly?

PS Sorry my English

Don, what PHP are you using for your website?

PHP Version 5.6.31
System Linux #deleted_by_me# 3.10.0-693.2.2.el7.x86_64 #1 SMP Tue Sep 12 22:26:13 UTC 2017 x86_64
Build Date Jul 6 2017 08:06:52
Server API Apache 2.0 Handler

By the way, I have just tried solution publicated by Luchen6. It really works! Thanks a lot, comrade!!!!

Luchen6 wrote: Since sometime I also had Mostly grey images on our site. Especially with portrait photo's taken with a phone or tablet.
It took some investigation and finally I made a changed in the file ../libraries/kunena/upload/upload.php.
The part // Get filename from stream and the belonging code on lines350 (about) I places outside the while loop. now it works fine!

Great news
I had some seriuos issues with it as well earlier. Was using exact same PHP as you do, but after updatering to PHP7, the problem was gone - so that would have been my suggestion for you to try.
But nevermind now - but everybody else - try update your php to 7, if its bugging in 5.

I tested this issue with php 7.
On my life site I only upgraded from php 5.? to 7 recently.
Maybe this issue was raised since then.
I did not check how the block size used during the copy is determined. This can be different by using an other PHP version.

It comes down that in my opinion there is no need to check the image orientation while copying the file. This is only useful after the file is completely copied.

Many thanks. It is fixed in the next version.