Designers, for both web and print media, mostly use tools like Adobe Photoshop and Illustrator for doing the creatives of a project. They'll do the prototypes in PSD format but, for approval, the designs are delivered as PDFs since their clients may not have the software (Photoshop in this case) that is required to view PSD files.
Read Photoshop (PSD), Fonts (TTF) and other files in the browser.
That said, if you have any Photoshop (PSD) files on your desktop that you want to view but without having to install Photoshop, here’s a tip for you – just go to your Google Docs account and upload the file.
Google has recently added support for new file formats in Google Docs that are commonly used to exchange design prototypes between clients and designers. That mean you can open and quickly read Photoshop and other files in the browser itself without requiring the application.
The file formats that can be natively viewed inside Google Docs, without conversion, include Photoshop (PSD), Illustrator (AI), Fonts (TTF), AutoCAD drawings (DXF) and Office 2010 documents (like DOCX, XLSX and PPTX).
And if the file that you are trying to open is already on the web, you don’t even have to bother uploading it to your Google Docs account. Copy the public URL of that file and pass it to Google's online viewer at docs.google.com/viewer.