Add option to disable loading media by default

[maxso-216]

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** Describe the feature request below ** Data saving feature is pretty essential for users with limited data usage.

For example, disabling image preview on mobile data, or reducing quality of image/video can greatly reduce data usage.

[twizmwazin]

I'm unsure if we have the option to change the resolution/quality of images and videos, but I think adding an option to disable loading images by default would be a great addition.