v2.3 definitely fixed one issue with files but it was due to a bug where we needed to set an option to completely overwrite a file. Previously, this bug occurred if a character encoding (non-automatic) was set and the file being saved was smaller than the size of the existing file on disk. The smaller file would write itself out but leave the remainer of the larger file's content in tact. But again, v2.3 fixed that so that shouldn't be the problem here.
I did a simple test similar to you and can see the same issue. Here's what I've done:
1) In Code Writer, create and save a new Simple1.html file that references an image in the same local folder. Open Metro IE and see it doesn't show the image.
2) In Code Writer, update text in the Simple1.html and save it. Refresh Metro IE and see text change but still no image.
3) In Notepad, create and save a new Simple2.html file that has the exact same text content as Simple1.html. Open Metro IE and see that it DOES show the image.
4) At this point, I would think it would be an encoding issue so I open both files in Araxis Merge and text diff them. There are no differences. I use Araxis Merge and Visual Studio and both say they have the same encoding. I then do a binary compare in Araxis Merge and they are identical.
5) In another competitive Windows Store text editor app, I create Simple3.html, again with the same text content and save it. Open Metro IE and see that like with Code Writer, it does not show the image.
6) In Windows Explorer, I copy Simple1.html (one with problem) to Simple1b.html and Simple2.html (one that works) to Simple2b.html. Open Metro IE and look at both files. Simple1b.html doesn't show the image, while Simple2b.html DOES soes the image.
7) Then I make a .zip file with Simple1.html (one with problem). I unzip it to another folder and rename it to Simple1z.html and copy it back to the original folder. Open Metro IE and it DOES show the image. This is baffling because it's the same file as Simple1.html, so clearly Windows/IE is causing some problem perhaps with metadata it stores. The .zip file breaks the chain of metadata.
8) Open all of the files in Chrome (desktop) browser and they all show images fine.
Can you run through the same process as what I did above and verify that you see the exact same thing? I'd like to report this to the IE team if you have the same results. Thanks!