WordPress image upload SLOW Year ago it was very fast, now very slow WHY? Post navigation [plugin for chrome] Screenshot YouTube [Gallery Plugin] image gallery photo gallery slide show plugin
To anyone who faces the same issue, the problem was caused by WP Smush. Once we deactivated it, images were uploaded within seconds. We use nginx and gzip is doing the necessary compression anyway.
Smush – Compress, Image Optimizer, Lazy Load, WebP Images
https://wordpress.org/plugins/wp-smushit/