Edit (may 6, 2014)
This issue is now solved. From IOS6 (dec 2012), Safari has access to the camera roll, so it is possible to upload images directly from Safari without the Dropbox workaround. That is, I can follow the steps 1 and 2 of the original question, and then upload it directly to StackExchange.
I leave the original question and its edits for reference.
Original question (jul 22, 2012)
Currently I am far from my computers, and I've got a lot of spare time, so I'd like to participate in this site and answer some questions, using my iPad.
I've found that the site is very iPad friendly, and that I can navigate, read and write answers without problems (specially if I use an external bluetooth keyboard, which make more accessible the markup symbols).
However, when I want to try out the code in my answers and post an image with the resulting output, I get into trouble. These are the steps that I'm currently using:
- I try the code using LaTeX previewer which is also very iPad friendly, to my delight.
- If the code works, and I want to paste the resulting output, I select the image and save it in the iPad Photo Album.
- Using Dropbox for iPad, I upload the photo from the iPad to some Dropbox folder.
- Using Dropbox again, I get an url for the uploaded image (which is a shortened url).
- Since stackexchange image upload service does not work with shortened urls, I use Safari to connect to that shortened url, download the image, and get the expanded url which points to the real
- I use stackexchange's image uploader to give the url of that image and finally get the result in the post.
This is how I answered Drawing node in tikz with both background fill and grid pattern?, for example. I wonder if there is a shorter method, or if I am the only one trying to do such a thing from the iPad.
EDIT (jul 23, 2012)
The reason for such a convoluted process is that in iOS (iPad, iPhone and iPod operating system) the filesystem is sandboxed for each application. In other words, an application has not access to the files created in a different application. The user has no control about where the files are stored. When you "download" an image with Safari, it "sends" that image to Photo Album app, which stores it in its private filesystem. But then, when some web page offers you to "upload" a file, Safari dismisses that option, because the only part of the filesystem that Safari can read is its own private space, and this is use for caching only. This is why I have to use Dropbox as an intermediate store.
However perhaps an iPad user more skilled than me knows about some workaround. It is a pain to be unable to upload files from the browser.