Ticket Information - ID: #641
| ID: | Category: | Severity | Reproducibility | Date Submitted | Updated By: |
|---|---|---|---|---|---|
| 0000641 | Bug Reporting | Low | N/A | 09/04/12 04:27AM | Jerl |
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| Summary: | Thumbnail has jpeg artifacts |
| Description: | The thumbnail and resized image for http://gelbooru.com/index.php?page=post&s=view&id=1637035 have very obvious jpeg artifacts. The full sized image has much less noticable artifacting. |
| Additional Info: |
Jerl replied at 2012-09-04 20:54:54  |
| I don't think this is actually an issue. While for full images, we definitely do prefer to have the highest possible quality available, thumbnails are a bit different. They're just a preview that someone looks at before deciding whether they want to view the fullsize image, so in reality thumbnails don't need to be very high quality. That being said, from what I can tell, this is simply a result of the compression artifacts in the original image being enlarged by the slight level of compression that is applied to all thumbnails in order to reduce load on the servers artifacting pre-existing artifacts. Ultimately, it's actually useful for the moderation team and for gardeners to be able to see this compression in the thumbnail, since it gives us a good indication that the fullsize version is likely to also be poorly compressed. For normal users, compressing these thumbnails reduces server load, which helps keep the site in general running faster. |
lkjh098 replied at 2012-09-04 21:18:44 |
| The image is large enough that it doesn't fit on most monitors (2357 pixels high), so for normal viewing you'd see a scaled-down version, which looks just fine. If you did have a monitor that good you'd have to lean really close to see any artifacts. The basic problem is that the image quality setting is appropriate for a large image with very low detail per pixel, but not for a scaled down thumbnail version. The pixiv scaled-down versions are totally crisp. |
Jerl replied at 2012-09-05 10:33:00 |
| I don't know, I see the artifacts, especially the macroblocking, if I lean back as far in my seat as I can, or even if I take off my glasses. To put that in scale, at the same distance with my glasses off, I can barely make out this text I'm writing. Additionally, I generally view the fullsize version of images, even if they don't fit on my screen without scrolling, in this size range. The image quality setting is very appropriate for a scaled down thumbnail version. Remember that Pixiv is a much larger website with a much larger budget. They have many more servers than Gelbooru does, so they have to worry much less about managing server load. Gelbooru, on the other hand, has to be kept in a fine-tuned balance in order for the site to load at all. What makes the thumbnail compression appropriate is the fact that people frequently load very large numbers of thumbnails, 28 per page. In the past, improvements have been made to the hardware JUST to increase the efficiency of serving out thumbnails. I feel that the site continuing to be stable is much more important than thumbnails looking pretty. |