Firefox 52.5.0
*Unable to capture screen. Please try again when the page has loaded.*
After restarting Firefox or even rebooting: copyfish icon greyed out.
Remove.

edit after reply:
Fair enough - I'll try the older version.
The 1 star is there because there's no zero star: meaning it does nothing.
I must add that Copyfish does work on Chrome, but until I get the full hang of it I'll refrain from giving one or more stars there. Besides I work in FF and only revert to Chrome if everything else fails.

edit2: It turns out it was not an older version, but a newer version where you have added support. Kudos to you for doing that.
However my one star was well deserved then. For there was nothing in the version history that even hinted at previous versions not being supported. Nor is/was there a requirements part.

This add-on is amazing! Works as described. Truly amazing!

I have tested this add-on using English, Japanese and Spanish text, and its yield has been surprisingly successful. Not perfect, but good enough.
I tried it on complex and difficult to read text (from blurry or pixelated photos) and the results, although not completely accurate, were sufficiently close, and in some cases 100% perfect after a few retries.
Copyfish cannot read vertical text at all (such as Chinese or Japanese) but horizontally formatted text is generally not a problem.
There are some quirks with it and the interface can be fiddly. A few times I found myself having to reload the whole page from the browser in order to make the add-on retry the OCR work since the buttons just stopped responding, but it was never more than a small time-consuming problem.
All-in-all this add-on may very well save you a lot of time typing from an image, specially if you don't have the means or ability to type from a language that uses a different alphabet than your own, be that Latin, Cyrillic or Hiragana.
:)

THIS ADD ON IS AMAZING

Doesn't work at all on Firefox 57.0b14.

UPDATE 9/11/17: It does a fair OCR job, for both languages (Greek & english) Only in some cases. Not always. It depends from the text on the picture I guess. The translation fails though, But I really don't need the translation and I have disabled it from the Options. I just need the OCR alone.
This tool is Not good for capturing URL links. Because I found this screenshot which is an example of the "error" popup window. from one web page and the text was: [[<>]]
I tried to OCR this, But it could only capture only the simple 2 lines of text: [The Requested file was not a valid file]
BUT the lines which have special characters couldn't recognize it: [C:\Users\.....]

* I have also tested it on the "dilbert.com" website (like you did on your example) and it works capturing text on Comic images.
I have noticed that sometimes It converts the (i) letter as a Number (1) and the (comma) as a (full stop dot) in some images.

* You should add the (Options Button) when we right Click on the Addon. It is a painful process to find the options to change the Language.

* Also on the Youtube video in (FIREFOX 56.0.2) I tried your Chinese example video and it works Great! => https://youtu.be/8dRWw4FIYqs
But on YouTube video, in the (CHROME Browser) it is Unable to capture the text. it shows me this Warning:
(Please try again when the page has loaded. Prevent this page from creating additional dialogs.)

*And last but not least, On another Comic Image Example it can not recognize this kind of text/font => http://www.leasticoulddo.com/comic/20170430/

Anyway, all in all, this Addon works fairly with Firebox 56.0.2!
I want to believe that in Future updates will be much better. I guess.

dont work at ff but all ok at googlehrome
sreanshot // http://prntscr.com/h1mfri
and how i can get small latter in place of big
sreanshot // http://prntscr.com/h1mhnc
i wanna small register for correct translation
and how change transleator at Google translate by example? Can u whreat me answer at my gmail pls

after update on 56.0.1 stoped work. but on previous version work fine. great addon. pls fix it

I upgraded to Firefox 57 Beta today and Copyfish works just fine.

I too have the issue with the addon not working. It says: "Unable to capture screen. Please try again when the page has loaded". Nightly 57

This addon looks cool. But it doesn't work for me. Each time it shows "Unable to capture screen. Please try again when the page has loaded". I have banned all other add-ons and use Nightly 57

Works great for Chinese and English (these are the languages I use it for)

Work perfectly .
The result need some corrections but it's very useful and simple to use.
Thanks!

I know a little about Chinese and China, so I know what the video you used to demonstrate this extension described. I do not think it is a good idea to involve this extension in political stuffs. At least I do not feel secure when using this add-on.

I have been watching video lectures and there are times I want to copy items. It has helped me a lot to convert instantly select a part of video and convert to text.

Try scanning 一百年前 、一百年後 or 網路如鴉片 it doesn't work.
Source picture URL
http://www.netize.net/04-chinternet-archive-fieldnotes

Like this add-on, really worth it for which it has made more

I've spent over fifteen minutes using this add-on and reading its page for basic instructions because this seems like a useful tool for an author. I click it on the top of my browser, it turns from black to gray, it prompts me to select text, and then....nothing. I create a new Word document to paste the selected text and the paste option is grayed out. This is either for developers or...has not been fully developed. -w.

Thanks for this addon !

It's a great tool. Thanks.

Let's appreciate that someone made an addon that did not exist before. Stop complaining for a free thing. And people spend their free time to create these free services that you are able to use.

Same as the other reviewer... "wait until page has loaded".

Perhaps they should make it compatible with the most popular addins like no-script and adblocker (I suspect that's where the issue lies)

Works absolutely fantastic on all sites I tested it with. I use it mainly for Youtube subtitles, chat translation and gaming. Sometimes you have to reload the page for Copyfish to work as the sites needs to load after Copyfish has been turned on (so it seems).

I love this utility because I have dished out good money for far lesser performing OCR products. This is a great extension!