zeitgeist said:
The reason for that is that I did the conversions in the original 320x200, the resulting image collage is just resized to 640x400 (well, 640x1200) so that people don't have to strain their eyes and/or use browser zoom to see pixels and artifacts and such. If you resave 640x400 images they naturally look much better.
Yeah, uhh... that's a bit herp-a-derp. Of
course if you enlarge a small image you make all the artifacting obvious. If for example I take the uncompressed JPG, resize it to the proper size, save it at 90% with chroma subsampling and then upload it to the gallery:
And yes, if you enlarge that, you very obviously see the artifacting because derp, you're enlarging all the artifacts that are designed to work at a smaller resolution. As it is, that image looks absolutely fine to me. It's three cars racing at 259 km/h. Point of posting image == made.
zeitgeist said:
(to clarify - the bottom image is actually the first JPEG (quality 90) resaved at quality 60, it's not the original PNG saved at 60 for the first time, to simulate the double saving)
My advice would be to upload higher quality JPGs as even at Q85 I'm still re-saving the image which means double-compression is still occuring. There's simply no way I can avoid artifacting because of the nature of the JPG compression.
As you say, if quality is your concern, use PNG. JPG is not an image format you should be using if you're concerned about the pixellating around your tiny screenshots from your old racing game that you're posting in your LP.
zeitgeist said:
And for JPEGs, it would be better to test the gallery resaving with some higher resolution screenshots. I mean, I doubt anyone would seriously upload a 320x200 in JPG in the first place?
I don't know, you just attempted to show how bad that would be (i dunno why lol?) and I've got another guy whinging about some artifacts around his text in what is a horribly shitty pastel image anyway that anybody who looked at I doubt would choose to complain about some issues around the
perfectly clear, readable text as their first complaint...
zeitgeist said:
Anyway, If you want to test the uploading on an 800x600 that still has lots of details to possibly mess up, try this and pay attention to the semi-transparent walls, and the pixel font:
That's the PNG re-saved at 90% with chroma subsampling and then uploaded to the gallery. I can still read the pixel font. Crisis?
Of course if you now re-sized that to x3 its size you'd clearly see the artifacting.
Of course if you stare at it all day you'll see the artifacting.
Of course if you open up the original and take quick looks between the two you'll notice the difference.
If this is the 75th image in your 120 image update though, nobody cares.
Now, here's the same image save at 80% (20% compression) with chroma subsampling then opened up and re-saved as a full colour PNG and uploaded (so there's no double-resampling what-so-ever):
Notice how all those problems that exist in the one above, the artifacting, the colour wash-out in the green text in the bottom right,
still occur? In actual fact that's even a bit brighter than the original.
Both have artifacting. Yet both are still readable. Both are poorer quality than the high Q PNG original. JPG is not for tight-asses who want pixel perfection.
Crooked Bee said:
Gosh, DU, just add a 80 or 85 compression option, and all will be right with the world. Or am I not following something?
This thread has become too technical for me.
No, the point is you'd still complain about that too. If you're complaining about the dithering in a 256 colour image or the shocking colour difference because a grey is not quite as grey as one of the greys in the original or the artifacting around text in a JPG has you screaming in terror, then you'll complain even if I did bupkiss to the image.
Just upload your images as full colour PNGs if you're such a quality tight ass. It's what that option is there for. I'm sure all your LP readers will appreciate your super-high quality images every update that they can study in fine detail and praise for being artifact free.