Hello,
I have changed 700x700 to 864x864 in view.xml
<image id="product_page_image_large" type="image"/> <image id="product_page_image_medium" type="image"> <width>864</width> <height>864</height> </image>
So, now the enlarged image is of same dimension.
I have also, disabled Javascript resizing on upload & set JPG quality to 100%
However, there is visible difference between Original image & Lightbox Image(right click image-> open image in new tab)
Additional, there is size difference in the Uploaded image & Original image, so definitely some image processing is happening. How to stop that?
Have also tried switching from GD to IMAGICK
Is there a way I can retain 100% image quality?
You can disable images resize https://docs.magento.com/m2/ce/user_guide/catalog/product-image-resizing.html
I had already done that and had added the screenshot too in my question.