So what is your policy on filters (it doesn’t say in your guidelines)? I get not using filters that drastically alter the image, but what about just lightening the photo up so the quality is improved without using a filter? Or even filters that only lighten the photo a little but don’t change the overall photo much?

postmaster Smiling Dogs

As long as the picture is still clear, not too washed out or too dark, then you’re good. Filters are fine.