Thanks to
@pegelli for suggesting a way to indicate both respect and boredom. Maybe we are pushing this topic a bit far but, if anyone wants to indicate respect, here is what I suggest.
1. If you think a photo is both boring and technically questionable, don't say anything.
2. If you respect the skill that went into the photo, but are bored by the subject matter use the "Wow" emoticon.
3. If you feel the poster has posted a really good and interesting photo, like it normally. The poster thinks it is boring so it is - to him. You are free to think it deserves to be liked.
The real problem with this topic is that, once our attention is drawn to an image here, we start to wonder why the poster thinks it is boring. For example,
@Shashin's images of a window and a road above are technically excellent. I think the road is also beautiful and I am now interested in why Shashin thinks these are boring. Wondering about this makes the images interesting. Aaargh. Starting to sound like one of those temporal paradoxes.
I encourage posting a little comment with each image, telling us why you think it is boring. For example, maybe you love it but your partner says it spews and no one noticed when it was posted online. Therefore, you suspect that people find it boring. I have lots of those.