Dotted picture problem

I had this picture scanned today, but it was done by someone at the store. They sent it by e-mail, I download it and unzip it. It says it's a .TIFF file, in inside PS it's classed at a bitmap.

So I am trying to edit it and I can't. I am looking online for converters and help but none of it works. Y'see I did find a way so I could edit it properly, but then none of the editing takes place. I try to change the contrast or something, the preview shows the change, but then the image doesn't change once I confirm. It's really odd.

Then I zoomed in to find this:



Very odd.

I don't believe I have ever seen this before. The image looks normal 'from a distance. Does anyone have any ideas on how I can fix it or what it means?

Thank you.

Try changing the color mode in Image->Mode menu or check the layer options. It might be locked.