[mistercow]

>So, will there be writing .PSD files as well?

Writing PSD files is considerably easier than reading them. To write, you need only support the features you actually use. To read, you must support everything. For example, Photoshop always saves its layers RLE compressed (or it did when I last wrote code to write PSD files, which was about five years ago), but the format supports uncompressed layer data just fine. So if you're just trying to get basic interoperation with Photoshop, you don't have to worry about RLE at all.

>Imagine: upload a .PSD and get back a clean HTML layout + bootstrap_overrides.css

Why would that require writing .PSD files?

[smtm]

Well, so you could iterate on your design - and pick up the changes made in CSS back into the design PSD. And work onwards from there