The postmark on this card was 1904, but I think the image is from around 1890.
It's a pretty good depiction, when you think that the artist couldn't have ever seen it from this angle. If you study it, you can pick out the features, like the fountain inside the main gate, the smaller one midway up the carriageway, the fountain in the smaller lake and the large lake to the right of that. On the left is the bandstand and 3/4 way up the image, running across left to right, the tree lined Broad Walk. I think that clearing in the trees on the right, a little higher is possibly The Devil's Rock and pretty central towards the top, the battlements (or whatever they're called) that the cannons were once on.
I'm not too sure about the very large property on the horizon, but it's situated right where the Corporation Park pub is, so I'm guessing it supposed to be that, though it's a bit out of proportion.
Note the horse drawn trams on Preston New Rd at the bottom. They were introduced in 1888, I believe.
Courtesy of the CP collection