I don't have a lot of sad anime pictures or at least, I don't remember saving them.
Although, there are some pictures that make me feel a bit down.
This one for example isn't sad at all but the style reminds me of internet forums back in 2008. This and, I guess, blingee are pretty nostalgic.
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Really off topic but I've always liked skies that are like this. When I still lived close to the sea I usually go to the beach at night, watch the pitch black sea and sky as I listen to some touhou music. The city behind me was quite bright though so nothing as impressive as in this picture.
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I should go back and watch darker than black again.
This one was my first pfp ever on the internet. I was 9 or 10 back then and still using yahoo messenger. I was still 5 years away from being able to read and understand words that are in this picture. I just copied someone else's pfp. Couldn't even make it out what it was on my 800x600 screen and yahoo's tiny avatar popup window.
Obviously, I didn't think much of it and haven't been keeping this picture. It was by pure accident that I saw it again in an old thread on a vietnamese tech support forum.
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There are quite a lot of these but I mean, me feeling nostalgic is hardly sad for anyone else hahaha.