I'd a problem reading & understanding a certain argument in an article on numbertheory. Not a big thing for any student with some experience with $\lim \inf()$ and $\lim \sup()$. So I copied (screenshot) 10 lines explaining the critical formula which I didn't grasp, hoping that either there was a misprint in the formula or I had such a basic misconception that it could be answered "with one sentence".

I got friendly comments helping my understanding, and I accepted one of the answers.

Crossed with that I got a comment introducing an aspect of illegality (page-scan in SE-network) and rudeness (screen-shots might be unreadable for some readers), a downvote on my question and an upvote on that comment.

The question is Correctly reading this $\lim \inf ()$ and $\lim \sup()$ expression?

For me it is such a misproportion of a harsh comment to a small question that I thought to simply self-delete the question and just take the given hints with me. The system-self-deleting-apparatus reminded me of disadvantages of such self-deleting of question once answers (and work of other members) are/is involved.

So I ask here: what to do best? I'm not going to OCR and/or manually type out the screenshot because it is perfectly readable and it were much more trouble than the size and weight of the question makes it worth. On the other hand there is indeed some kind help by some users, so that SE-engine's advice is acceptable. At the moment I've simply removed the screenshot to satisfy the commenter with his "forbidden"-aspect.

  • 4
    $\begingroup$ How about just ignore that comment? Now you have made an edit so that others will need to copy and paste the link in order to see the question. That seems to be worse than the original one. $\endgroup$ Commented Apr 30, 2019 at 19:13
  • 5
    $\begingroup$ Just this once I have converted the image into text. To be fair it didn't actually take too long. However, images are not a good way to present mathematical text/equations on MSE. $\endgroup$
    – TheSimpliFire Mod
    Commented Apr 30, 2019 at 19:31
  • 3
    $\begingroup$ @ArcticChar My comment brings up the difficulties experienced by users of screen readers. Under our "be nice" policy, SE tries to be more caring to users, especially new ones. In this spirit, it's unacceptable that the needs for the disabled be ignored. $\endgroup$ Commented Apr 30, 2019 at 20:40
  • 4
    $\begingroup$ Just to close the case: Many thanks to @TheSimplifire for your help. To [@]Gnusupporter - your reaction was for me just monstrous. Something like a reminder "please think of disabled person and convert your scan into text" or so would have done the job - why not trying to start with such small and kinder intervention before take out the hammer? I've stopped editing wikipedia for coming across such use of "the-big-hammer" because I think it has become just some other type of people's realm and I don't want to interfere more ... Well, I'll leave this now as it is. Thanks for any input! $\endgroup$ Commented May 1, 2019 at 1:53
  • 1
    $\begingroup$ There are circumstances in which images are preferable, perhaps indispensable, to conveying a problem setup. While it is often possible to replace much or all of what are posted as images with $\LaTeX$ expressions, this is something many Community members are happy to help with, a shared burden for those concerned with "collecting and curating excellent content." $\endgroup$
    – hardmath
    Commented May 1, 2019 at 4:16
  • $\begingroup$ @WillJagy As OP has said, the system prevents him to self-delete his own stuff. $\endgroup$ Commented May 1, 2019 at 7:38
  • $\begingroup$ I am sorry for my big hammer. Thanks for your suggestion. I will revise my comment template to incorporate your suggested sentence into it. Would you feel comfortable with relevant links added above your sentence, like "please think of disabled persons using screen readers and convert your image into text"? $\endgroup$ Commented May 1, 2019 at 7:58
  • 2
    $\begingroup$ @GNUSupporter8964民主女神地下教會 - yes, that were a well balanced style of intervention. And thanks for your "I'm sorry". Helps me to really leave it aside now... $\endgroup$ Commented May 1, 2019 at 9:04
  • 10
    $\begingroup$ @GottfriedHelms While GNUSupporter may not have phrased the criticism in the most polite way, I do believe you are engaging in gaslighting here. Not only was the criticism fair for the problem, but you immediately began calling the criticism "monstrous", "grossly overcriticism", among other remarks. And, you seem to be trying to earn sympathy for your situation by referring to your unsureness of site policies. I'm very much not a fan of, quite frankly, this blatant manipulation. $\endgroup$ Commented May 1, 2019 at 14:03
  • 1
    $\begingroup$ @GNUSupporter8964民主女神地下教會 I don't think you need to apologize or justify your comments here, but I do appreciate you doing so. $\endgroup$ Commented May 1, 2019 at 14:04
  • 1
    $\begingroup$ @DonThousand Thanks for your opinion and your analysis to the problem :) The idea of "be nice", apart from SEO-friendliness, takes an important role in my anti-text-image stance. However, as the wording in the linked comment is far from "nice", I feel an apology is the 2nd best thing I can offer, while the best thing is a detailed explanation below. $\endgroup$ Commented May 1, 2019 at 14:47

1 Answer 1


I am the "commenter" that you're referring to in the last sentence. Before explaining anything, I would like to draw your attention to the benefits of having things properly typed.

More efficient (math) searching

We can easily find a bunch of questions with math expressions like "$n < 2^n$" with the help of Approach0.

Approach0 Logo
Figure 1: Logo of the math search engine Approach0
Image source: Approach0's GitHub profile

approach0 math search box
Figure 2: Approach0 search for "$n < 2^n$" with "induction".

approach0 math search results
Figure 3: corresponding Approach0's search results

As we can see from Figure 3, the matched expressions get $\bbox[yellow, 1pt]{\textit{highlighted}}$, notably "$\bbox[yellow, 1pt]{\textit{induction}}$" and "$\bbox[yellow, 1pt]{n < 2^n}$". Moreover, it can also $\bbox[yellow, 1pt]{\textit{highlight}}$ "$\bbox[yellow, 1pt]{k < 2^k}$". That's not something that usual web search engines (including the built-in one on SE) would do. This helps the community to spot out possible duplicates despite difference in the choice of variables.

Improved accessibility

People with disabilities have been contributing to our communities, we shouldn't exclude them from participating in the SE network, which favors a "be nice" policy.

enter image description here
Figure 4: A visually impaired person using a screen reader
Image source: YouTube

Unluckily, text images (image files whose content is text) pose technical difficulties to screen readers. Thus, text images hinder those using screen readers, such as the visually impaired, persons suffered from reading and writing disorder, from participating in SE.

As the name "Stack Exchange" suggests, this network promotes and facilitates the exchange of ideas between individuals. In the next section, you're going to see why SE's moderators are against the use of text images.

Despite Euler's blindness, he had been contributing to the math that we're now using. While making use of the math that disabled persons have contributed to, should we stop disabled persons from reading our posts?

Figure 5: Leonhard Euler
Image source: Wikipedia

SEO friendly

"Google Does Not Extract Text from Images"

enter image description here
(Image) source: Did Google Just Read the Text on My Image and Can This Affect My Rankings? by Razvan Gavrilas

If everything has been typed out, then a web search engine can interpret its content. Compare these two version of the question in terms of SEO:

  1. Original version of the main site question
  2. Typed out in $\rm \LaTeX$ by @TheSimpliFire.

Google sees an image by its alt attribute. In your main site question, it's "image", which is not descriptive. Therefore, your image alone can hardly be useful to the search engine. In general, it's advised to give descriptive alt text to a web image.

From the previous comparison, it's clear why SE moderators and staff prefer users to "type everything out".

My response to your remarks

For me it is such a misproportion of a harsh comment to a small question that I thought to simply self-delete the question and just take the given hints with me.

(Edited in response to @TBonger's comment)

I began with "please", and provided links to relevant meta posts for further info. I can hardly see any harshness in my comments.

I've misused the word "forbidden" in my comment. There's no mechanism stopping the upload of text images on SE. I should have said "discouraged" instead. My apologies for OP.

The system-self-deleting-apparatus reminded me of disadvantages of such self-deleting of question once answers (and work of other members) are/is involved.

In general, one should never self-delete his/her own question after receiving an answer. In particular, on Math.SE, it's OK to self-delete his/her own question only if the only existing answer is a non-mathematical one.

For your question, you have received more than one answer, so the system won't let you self-delete your own answer to avoid content loss of the site.

So I ask here: what to do best?

The linked Meta.SE answer has already answered it.

"Type everything out, so it is all searchable."

Hiding your image from display while leaving the link doesn't improve the clarity of your question. As other users point out, that's even worse: that can't help users using screen readers, but that also hinders normal users from viewing the content. As one of my links in my comments to your main site question suggests, your question should "contain sufficient context to be answered without the external context" (i.e. the screenshot of your PDF).

Remarks: No matter your text image is a from a book/a PDF, no matter it is scanned or screen captured, the idea of SEO-friendliness still applies.

  • 1
    $\begingroup$ @AlexanderGruber Thanks for edit. $\endgroup$ Commented Apr 30, 2019 at 20:34
  • 3
    $\begingroup$ No problem-- ought to help some of our mobile-using friends. $\endgroup$
    – Alexander Gruber Mod
    Commented Apr 30, 2019 at 20:37
  • 7
    $\begingroup$ You say that "I can hardly see any harshness in my comments," but I think that it's worth mentioning that harshness is best measured in terms of how the comment is received, regardless of how it was intended. And I think that a comment that specifically emphasizes (even down to the italics) that the user's actions are "forbidden" is harsh at best and downright rude at worst. $\endgroup$
    – user296602
    Commented Apr 30, 2019 at 20:39
  • 1
    $\begingroup$ @T.Bongers Thanks for explaining. I'm editing my answer to reflect this. My apologies. $\endgroup$ Commented Apr 30, 2019 at 20:45
  • 9
    $\begingroup$ @GNUSupporter8964民主女神地下教會 For what it's worth, I think that this is mostly an issue of using too-dramatic language ("forbidden," "unacceptable," etc.) combined with overuse of italics. I'm sure you don't intend it to come off this way, but in a written medium it's pretty harsh. And as an aside, the overuse of italics and bolding and overformatting makes your answer rather uncomfortable to read; perhaps this is just me. $\endgroup$
    – user296602
    Commented Apr 30, 2019 at 20:47
  • $\begingroup$ @T.Bongers Sorry for such harshness. That's also me, or what I perceived. Imagine that you can no longer see anything like Euler, or you have reading and writing disorder, or hyperactivity, so that you can't read by eyes. What would you feel if you hear nothing from a page from your screen reader? $\endgroup$ Commented Apr 30, 2019 at 21:02
  • $\begingroup$ @GNUSupporter8964民主女神地下教會 Your own post has six separate images, several of which have text content.... $\endgroup$
    – user296602
    Commented Apr 30, 2019 at 21:05
  • 2
    $\begingroup$ @T.Bongers I'm going to revise my comment templates after this so as to take your advices and opinions into account. Sometimes, even though we can't see, we can hear. Regarding the use of pictures, here's a set of principles that I know. In my answer, figures 2,3 & 6 contain text. All of them are for illustration purposes. It's fine without the first two, but I prefer using them. For the last one, the text label are necessary for illustrating Google's search result: you can't illustrate an idea without explaining what's an arrow for. $\endgroup$ Commented Apr 30, 2019 at 21:16
  • 1
    $\begingroup$ @GNU This is an absolutely excellent answer. If you get some time, would you mind copying over the relevant parts of this answer to this canonical Meta SE thread? Thanks! $\endgroup$
    – user568976
    Commented May 6, 2019 at 16:31
  • $\begingroup$ @Blue Thanks for invitation and done! $\endgroup$ Commented May 7, 2019 at 7:44

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .