I was able to solve this using this solution from the above mentioned thread.

I can confirm this issue. Uploading an average size image results in this error in the browser console:
POST http://mydomain.com/wp-admin/async-upload.php 500 (Internal Server Error)

PHP Logged this error within 5-10 seconds after starting the upload – NOT 30 seconds:

[14-Apr-2016 22:32:29 UTC] PHP Fatal error:  Maximum execution time of 30 seconds exceeded in /home/content/path/to/my/html/wp-includes/class-wp-image-editor-imagick.php on line 370

When switching to Twenty-Sixteen there were no upload errors on any image uploads (including very large images).

I was able to verify the following:

• Image does get uploaded to the correct year/month folder
• Images do get crunched into 16 various sizes
• In Media Library, image receives default placeholder icon (gray page)
• Clicking the icon and then “Edit more details” link, the image is displayed on the image on the Edit Media page
• Clicking the “Edit Image” button below the image results in “Image data does not exist. Please re-upload the image.“

Memory Increase & Other Hacks
I’ve completed all the requisite settings:

// .user.ini
upload_max_filesize = 128M
post_max_size = 256M

And tried all the .htaccess tips from these posts with no success:
– Here
– And Here
– Also tried disabling all Plugins

Upload Scenarios
Here are a couple image scenarios that threw errors when using the Enfold theme but upload with no problem with default WP theme. As with comelen, sometimes larger images work where smaller files do not (both file size and image dimensions).

Scenario 1
Image type: png or jpg
File size: 24kb
Dimensions: 1600×900 @72dpi
Work-around: After much experimentation with dimensions, I discovered the file would only upload if under 1200px, so I upload the file 1199×674.

Scenario 2
Image type: png or jpg
File size: 173kb
Dimensions: 480×854 @72dpi
Work-around: none (other than switch to Twenty-sixteen)

• Enfold v3.4.7 (although I’ve experienced this issue on several previous versions)
• PHP v5.4.42
• WordPress v4.5
• MySql v5.5.43

Honestly, the last place I suspected was the Enfold theme because it’s always been rock-solid! Let me know if there is anything else I can do to help resolve this issue.

Thanks,

Jeff Boothe

** UPDATE 4/15 **
Just got this PHP error when attempting upload:

[15-Apr-2016 22:31:34 UTC] PHP Fatal error:  Maximum execution time of 30 seconds exceeded in /home/content/p3pnexwpnas10_data01/24/2579924/html/wp-includes/class-wp-image-editor.php on line 423

• This reply was modified 8 years, 8 months ago by topearn.