Image compression on SGL

[Space Cowboy]

All images uploaded to SGL and those already in the albums are now highly compressed which has destroyed image quality.

Without causing a riot, has anyone got thoughts on this?

 

[Elp]

Never rely on internet services for anything.

[TiffsAndAstro]

Its how the internet works?

Personally I'm grateful we can upload images for free.

If you want an online archive you could try uploading .fit etc

[PeterStudz]

What I find strange is that it’s also being done to images of tiny size - say 12-15KB compressed to ~3KB. Doesn’t seem worth the effort. And you get better compression if you post on say X/Twitter. If you haven’t tried X, don’t bother, it’s pants! 

Then as it’s free I can understand why. 

Edited October 24 by PeterStudz

[vlaiv]

I've just checked.

Originals are kept as they are - you can go into your profile / attachments to see actual high quality image.

It is probably just a setting - once image is requested (on page load of particular thread) - cache is examined and if compressed version is found - that one is served, otherwise new compressed version is created on the fly and stored into cache.

One can probably change compression settings, and if one deletes current cache - all images will be "recompressed" when requested to new settings and different quality.

This is done to save the bandwidth.

[PeterStudz]

For beginners/new users to the site it isn’t obvious that if you click on an image you can get a higher quality. It took me ages to realise.

I’ve already seen people linking their image from other social media sites that have less/better compression. Which kind of defeats the point. 

[geoflewis]

1 hour ago, vlaiv said:

Originals are kept as they are - you can go into your profile / attachments to see actual high quality image.

Thnaks Vlaiv, so are you sayng that they are still there as uploaded, but only the OP (and presumably Admin) can see them, as only compressed cached versions are available when viewing a public thread?

[Mr Spock]

Clicking on the image doesn't work. There's a report to admin here. Please follow that. 

 

[geoflewis]

1 minute ago, Mr Spock said:

Clicking on the image doesn't work. There's a report to admin here. Please follow that. 

 

Nice try Michael, but that thread got 'compressed' out of sight....🙄

[vlaiv]

10 minutes ago, geoflewis said:

Thnaks Vlaiv, so are you sayng that they are still there as uploaded, but only the OP (and presumably Admin) can see them, as only compressed cached versions are available when viewing a public thread?

It appears so. You can check your attachments to verify.

Go here:

and you will get list of your attachments.

Here is my list with above image:

If I click to download it - I get original at 20Kb. If I however click on the first image in this post and open it in a new window (I need to actually post this so I can check image size, I'll update this post as I do that) I get : ....

image.png.51b2fe5337a7af744c380309de6c8209.png

and that is 6.71Kb compressed webp image in fact.

 

 

Edited October 24 by vlaiv
added info

[geoflewis]

1 minute ago, vlaiv said:

t appears so. You can check your attachments to verify.

I already checked, but the main reason for posting images is to share them and for planetary images compression destroys the fine detail we want to share, so it becomes somewhat pointless.

[Zermelo]

I have the opposite issue. If there's a new entry in my "unread" view that has images, then even the thumbnail versions that are displayed in the post summary can take a couple of seconds each to generate (line by line). My phone isn't the fastest, but even so, it suggests that the versions of the images being served are quite bulky.

[vlaiv]

8 minutes ago, geoflewis said:

I already checked, but the main reason for posting images is to share them and for planetary images compression destroys the fine detail we want to share, so it becomes somewhat pointless.

Well, I can see couple of ways we as a community can deal with this.

- We can "file a complaint" with admin to see what can be done about it

- We can try to manually "circumvent this" by adding a link to original attachment as a link instead of embedded image (might not work - I'll try it now):

(click here to view original image)

- We can ask administrative team to try to add this as a shortcut next to "insert this attachment into post" - something like "insert link to full size into post" kind of action

- We can ask administrative team to give us option to choose what "level of compression" images in our post have - like standard quality (for screen shots and general images) and high quality for astronomical images

 

(above link works - but it triggers download instead of view)

Edited October 24 by vlaiv
added info

[vlaiv]

I just thought of another way this might be handled (inspired by above post by @Zermelo)

- we can actually ask admin team to add "icon" next to image that will be labeled as "display HQ version". This way each person could decide if they want to view HQ version of particular image.

This would save bandwidth by default but would let interested parties view the image in high quality.

[Kon]

I liked the simplicity of just adding the PNG and it was displayed at original resolution. It's a very recent thing and I don't know what is going on.

I don't think is a cashe thing as I see it across all my devices even at work with super high speed ethernet.

Your solution didn't quite work Vlaiv as it just downloaded the image. Yes it's high resolution but I don't want to download images for everything I look at sgl.

Let's see if the mods have a reply or solution to my post.

[Mr Spock]

I've just accessed the site from Firefox where I'm not logged into anything anywhere. Obviously I can't see the Bugs section as it's members only. However, when I look at the "What did you see tonight" thread I can see the image I linked from Facebook looks normal. So it is definitely a site compression issue as a link displaying ok.
I believe this started sometime Monday as an image posted in the morning was fine, and one posted in the evening was not.

[Space Cowboy]

Thanks Vlaiv for your extensive knowledge. At least we know the original file format is in the bowels of SGL and a simple way of linking to that on the imaging threads seems the most sensible solution.

I can only think the mods have been unaware of this blanket image compression else they would surely have notified members before it came into action.

 

[Kon]

22 minutes ago, Space Cowboy said:

Thanks Vlaiv for your extensive knowledge. At least we know the original file format is in the bowels of SGL and a simple way of linking to that on the imaging threads seems the most sensible solution.

I can only think the mods have been unaware of this blanket image compression else they would surely have notified members before it came into action.

 

Stuart, can you put your two images in this thread please? Grant is looking into it.

 

 

Edited October 24 by Kon

[Space Cowboy]

11 minutes ago, Kon said:

Stuart, can you put your two images in this thread please? Grant is looking into it.

 

 

I assume you mean the 2 Saturn images, one uploaded on here and the other linked from outside?

 

 

I hope this has worked as I've copied from original thread. 

First image is uploaded onto SGL and 2nd linked from outside.

[TiffsAndAstro]

2 hours ago, PeterStudz said:

For beginners/new users to the site it isn’t obvious that if you click on an image you can get a higher quality. It took me ages to realise.

I’ve already seen people linking their image from other social media sites that have less/better compression. Which kind of defeats the point. 

Is this the "clicky dance" I've seen mentioned?

[PeterStudz]

8 minutes ago, TiffsAndAstro said:

Is this the "clicky dance" I've seen mentioned?

Since I don’t have a PC it’s more of a “finger dance”!

[vlaiv]

2 hours ago, Kon said:

I don't think is a cashe thing as I see it across all my devices even at work with super high speed ethernet.

It's not your local browser cache. It's cache on dedicated media server for the SGL.

Once you open the page - your browser requests all images on that page from SGL and SGL decides how to handle those requests. It has option of serving original content or compressed version to save bandwidth - but it would be silly to always compress original content for each request - waste of processor time and resources so once image has been compressed for "first showing" - it is kept in local SGL media cache (under slightly different name than one you used for upload - some numbers appended).

If you delete this cache - compressed versions - no harm is done, next time someone asks for the same image - original is again taken and compressed and served (and this is the point where you can intervene and have different compression ratio configured - or rather if you configure different compression ratio it is enough to invalidate that cache and all the images will be served with new compression ratio from that point onward).

[Kon]

36 minutes ago, vlaiv said:

It's not your local browser cache. It's cache on dedicated media server for the SGL.

Once you open the page - your browser requests all images on that page from SGL and SGL decides how to handle those requests. It has option of serving original content or compressed version to save bandwidth - but it would be silly to always compress original content for each request - waste of processor time and resources so once image has been compressed for "first showing" - it is kept in local SGL media cache (under slightly different name than one you used for upload - some numbers appended).

If you delete this cache - compressed versions - no harm is done, next time someone asks for the same image - original is again taken and compressed and served (and this is the point where you can intervene and have different compression ratio configured - or rather if you configure different compression ratio it is enough to invalidate that cache and all the images will be served with new compression ratio from that point onward).

Got you! Interesting that this is only a recent thing. Lets' hope SGL can sort it soon....or you might be up for the challenge 😉?!

Edited October 24 by Kon

[Vroobel]

4 hours ago, Mr Spock said:

I've just accessed the site from Firefox where I'm not logged into anything anywhere. Obviously I can't see the Bugs section as it's members only. However, when I look at the "What did you see tonight" thread I can see the image I linked from Facebook looks normal. So it is definitely a site compression issue as a link displaying ok.
I believe this started sometime Monday as an image posted in the morning was fine, and one posted in the evening was not.

I uploaded one of my most recent images on Saturday, 12/10 early in the morning and it showed the improper compression then. I had to place the following info: (Please open the image fully, it looks weird when displayed as the thumbnail image.)

 

 

Edited October 24 by Vroobel

[Grant]

An update on this - we are looking into it.

The files are not being changed once uploaded, the issue is the forum cloud server we use are experimenting with some different CDN providers which sit in-between users and the stored data. This one appears to be compressing and converting to webp images on the fly. The original data is fine and it may not be affecting everybody on all devices.

I've asked them to look at this and turn off any kind of webp or compression settings for us as it is clearly causing issues.