post - Upload images to Imgur from Mathematica

Question

Here's a challenge to all mathematica tag followers. Let's make it a lot more convenient to insert images into SO post from Mathematica by creating an imgur uploader.

How can we create a function imgur[g_] that will rasterize its argument (making sure that the final size is not wider than the width of StackOverflow posts), convert it to PNG, upload it to imgur, and return a ready to be pasted MarkDown line such as ![Mathematica graphic](http://i.imgur.com/ZENa4.jpg) ?

Useful references:

• Imgur API
• Example of using POST request from Mathematica on WRI blog (posting to Twitter) by ragfield
• Example of using POST requests from Mathematica on SO (uploading to ifile.it)

I failed to adapt this latter method to uploading an image without exporting it to a file first.

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Warning, use with care! StackOverflow uses a separate imgur installation that keep images indefinitely. If you use the main imgur, the images will disappear after 6 months if no one views them. Unfortunately as of 2011 November there seems to be no official way to upload images to StackOverflow programmatically.

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Update: See below a solution for uploading to StackOverflow directly.

Answer 1

A little bird just informed me of a Mathematica solution to this question (the underlying implementation still uses JLink, but this answer hides all the java related code):

imgur[expr_] := Module[
 {url, key, image, data, xml, imgurUrl},
 url = "http://api.imgur.com/2/upload";
 key = "c07bc3fb59ef878d5e23a0c4972fbb29";
 image = Fold[ExportString, expr, {"PNG", "Base64"}];
 xml = Import[url, 
  "XML", "RequestMethod" -> "POST", 
  "RequestParameters" -> {"key" -> key, "image" -> image}];
 imgurUrl = Cases[xml, XMLElement["original", {}, {string_}] :> string, 
  Infinity][[1]];
 "![Mathematica graphic](" <> imgurUrl <> ")"
]

This is V8 only and the XML import options "RequestMethod" and "RequestParameters" are undocumented and experimental (and therefore subject to change).