There's a size limit: 16-megapixel images and 1080p video is the maximum allowed for the free service, which offers otherwise unlimited storage capacity. Once uploaded, Google uses compression to save space on its servers.
If you don’t want your visual memories tampered with, the original photos can be uploaded as .RAW or .TIFF files and stored as-is there in the cloud. Once the first 15GB of free Drive space is full, users must pay Google $10 a month for a terabyte of extra capacity.
So, in other words, you can have free unlimited storage space for photos and videos if they are compressed, or you can pay a monthly fee for 1TB of storage for uncompressed material. This is assuming the service survives the same axe that eventually fell on Google Code, Glass, Talk, Wave, etc – it probably will. Probably.