There is a site which have a lot of images of high quality because of which the load time of site is quite high. It is impossible to optimize images one by one as we have many images. So could anyone please let me know how it I optimize all the images??
You can try to go for a few modules which do this job. Please find this free one https://www.apptrian.com/image-optimizer-for-magento.
You can also install the Google Page Speed Module in your server does the job perfectly along with other optimizations.
For better optimization you need to resize the images.
You can try the below example to resize the images as according to your requirement :