Change the compression-level of uploaded images and thumbnails. Get better image quality or save bandwidth.
Get better uploaded quality or save bandwidth: Change the JPEG compression-level of uploaded images and thumbnails.
The WP Resized Image Quality plugin lets you change the compression-level of uploaded images and thumbnails. Set it for maximum quality when you want images to look their best, or take advantage of lower quality settings to save bandwidth.
The admin page uses an easy slider to set the compression level, making this easier to use than other compression plugins or functions.php settings.