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## LaTeX Preview is working again!

 Quote by Fredrik Most of my posts are like that, so avoiding LaTeX isn't really an option for me. The "editing in progress" trick is only good enough for posts that have very little LaTeX content. So if this problem can't be solved, I would either have to get a new account or stop posting. I'm writing this on a fourth computer, and I still get the same images when I preview. It's not the latest images or anything like that, but always the images from the post I linked to. I just did some more testing and noticed that if I put more than 15 LaTeX images in my post, only the first 15 are messed up in the preview. The 16th is displayed fine. Maybe I'll use that as a workaround for a while.
I'm having exactly the same problem as Fredrik, except for me the number is not 15 but 2. Always. And the 2 corrupted images I see are always the same images every time. They are two equations that I once generated some time ago (probably the first Latex I created after it got reenabled after the disk problems).

I suspect that something went wrong in the past, some images got cached (on the server) in such a way that the cached images take precedence over freshly generated Latex in previews. Different users have a different number of "badly cached" images. For me it's 2, for Fredrik it's 15, for many lucky souls it's zero.

So a workaround is to stick a load of dummy latex images at the top of your post while previewing, remembering to delete them again before posting.
 Recognitions: Gold Member Science Advisor Staff Emeritus Okay guys, I added a bit of code that actively deletes stale preview images before generating new ones. That hopefully means the images will no longer be cached (by any entity -- our server, intervening proxy servers, or the browsers themselves). Let me know if anything changes for you. Since some of you have this problem no matter what computer you use, etc., I'm worried there's actually a caching proxy server upstream of you, even if it's usually transparent. - Warren

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 Quote by chroot Okay guys, I added a bit of code that actively deletes stale preview images before generating new ones. That hopefully means the images will no longer be cached (by any entity -- our server, intervening proxy servers, or the browsers themselves). Let me know if anything changes for you. Since some of you have this problem no matter what computer you use, etc., I'm worried there's actually a caching proxy server upstream of you, even if it's usually transparent. - Warren
The problem seems to be fixed, for me at least. Thank you!

Mentor
 Quote by chroot Okay guys, I added a bit of code that actively deletes stale preview images before generating new ones. ... Let me know if anything changes for you.
Thank you. It's working fine for me now.
 Mentor I just noticed another problem. Maybe it's only when I preview. I'll have to post this to find out. If I write f'(x), it appears as f single − quote(x). $$f'(x)$$ Nope, it looks fine when I post it.

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 Quote by Fredrik I just noticed another problem. Maybe it's only when I preview. I'll have to post this to find out. If I write f'(x), it appears as f single − quote(x). $$f'(x)$$ Nope, it looks fine when I post it.
Fredrik,

Fixed that one too. All should be well in LaTeX-land now.

- Warren
 Mentor Thank you. We're lucky to have you here.

 Quote by mattmns $$2 + 2 = 4$$
$$2 + 2 = 5$$

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 Quote by Unit $$2 + 2 = 5$$
That is true, modulo one.
 $$\sum(A+BX_{i}-Y_{i})^2=0$$ $$\mbox{just practising}$$
 Recognitions: Gold Member I've just given up on trying to post an answer because in preview all of my Latex stuff is showing images from a previous post ages ago and refuses to show the stuff I've entered today. I've cleared the browser cache and restarted it before trying again and that didn't help. What else can I try? For example, the following expression is displaying in preview as v2/r which I used in a post some weeks ago: [TEX] \frac{d\mathbf{p}}{dt} = \frac{E}{c^2} \mathbf{g} \left ( 1 + \frac{v^2}{c^2} \right ) [/TEX] Edit: When I submitted this one, the LaTeX now appears as a broken image marker.
 Mentor Johnathan: You need to use lowercase letters for the tex tags. Is it just me, or do we now have to refresh after every preview to get the correct latex expression to show up?
 Blog Entries: 9 Recognitions: Science Advisor There's an ongoing problem with LaTeX used in blogs and PMs. The image files in this case have "preview" URL, and you often get the wrong image. The problem is described also in thread TEX broken?. I've just checked and the problem is still there.
 Mentor I'm not sure if you posted that to report a problem, or if it was a reply to me. I'm aware of the need to click reply and preview, to get the LaTeX to look OK when you receive a PM. But that's not what I was talking about. I've been making a bunch of posts today, and every time, the LaTeX is messed up when I preview. (Older images are displayed). It doesn't help to just click preview again. I have to click my browser's refresh button, and then the resend button that shows up. And if I make any little change, I have to repeat the procedure.
 Blog Entries: 1 Recognitions: Gold Member Homework Help Latex preview is working fine for me, but I see old images for latex in private messages and profile visitor messages.