Have you confirmed that it is the resized image file itself that is glitched and it’s not a display artifact? Is this a problem only with images resized through the WP image editor? Or does it happen to uploaded images sized to standard sizes (large, medium, etc.)? Can you reliably cause this to happen, or does it occur intermittently at random? Is the issue with a particular image format like .jpg, .png, etc.?
The image processor that WP uses is part of your server’s PHP package, either GD or Imagick. All WP does is tell it what size is desired, so any glitches are most likely caused by the image processor itself. Which PHP version are you using? If applicable, consider upgrading to PHP 7.3.
The image is in a slider (i use “Smart Slider” plugin) and make them with photoshop (site 1920×900). It’s in PNG format, and it’s happening randomly (on updates for example) and the issue is only with the slider.
I use PHP 7.4 GD
Thanks a lot for ur answer – sorry for my broken english
