If you don't feel like providing the original images to viewers, you can enable DpiApp's 'Low-Res Mode', and DpiApp will automatically blur all images inside this gallery.
Generally, DpiApp will rescale each image of this gallery to 50%, then scale back to the original size. After this process, the resolution is lower but the size remains the same.
You can go to the gallery you want to enable 'Low-Res Mode', then click on the 'gear' button to switch to 'Gallery Settings' tab, you can then toggle the 'Low-Res Mode' item to 'On', and it's done! Your images inside this gallery will be automatically blurred/low resolutionized when viewers see them. You can also check them yourself by clicking into each image in your gallery. Or visit the share link you might provide to the viewer to check how the images look like.
Yes! DpiApp supports both gallery-wise blurring and image-wise blurring. Just click into the image you want to blur more, and set the 'rescale' field to lower than 50%, and click Update Gallery Image button to persist change. You can then see if you like the current resolution in the same page. Usually 50% is good for 720P~1080P images, 15% is good for 4k images.
If you want to serve a low res image to viewers, you need to first enable 'Low-Res Mode' in the gallery setting. Then you can set image-wise resolution on the image's edit page. If you can't see the 'rescale' field, please check whether you have enabled 'Low-Res Mode' in the gallery setting, if not, enabling 'Low-Res Mode' will resolve this problem.