Is it possible to build a grid of silicon photosites to build a digital camera at home?
Because discrete photo-sensitive components (LDR or photo-transistor, or PV cells or whatever) have significant physical size, you will end up with VERY LOW effective resolution because the space between the sensors will likely be much larger than the sensitive areas themselves.  

Not to mention the issue of scanning/multiplexing, etc. 10,000 or more sensors.

If you mean actually creating an array of photo-sensitive diodes (or whatever) into a MONOLITHIC silicon substrate, then it would appear that the old rule applies:  If you have to ask, you probably can't do it.  It takes millions of $$$ worth of very specialized equipment to process IC wafers. 

Not to mention cleanroom environment, and knowledge of design and manufacturing techniques. Not to mention raw materials (wafers, dopants, gases) that would be very difficult to source if you are not in the industry and have big piles of money.