There is no such thing as IOS 10.6. IOS the operating system for IOS devices such as iPhones, iPads & iPods. OS X is the operating system for Macintoshes, the current release is 10.11 (El Capitan). OS X 10.6.x (Snow Leopard) is a much older version of OS X. I believe the last Mac that came with Snow Leopard were 2011 Macs.
To answer your question get the file from the Windows box to the Mac and then use the Preview App (Applications - Preview) to open it. You can also right click the file and select Open With and then choose Preview or you can simply drag the file to the Preview icon in the Dock. Once open in Preview you may need to save it in a format Photoshop can understand.
Regarding your scanner, it may work just fine with OS X. Use the Image Capture app you already have in OS X to scan the document and then you wont have to go through all these gyrations. If you are not familiar with IC then please click Mac Basics: Using a scanner - Apple Support If for some reason the scanner cannot be found then check to see if your scanner is supported by VueScan (www.hamrick.com), it likely is.
From what I can tell you are making your work flow much more difficult than need be.
