The SSD only improve read and write performance to/from the storage device. It also uses less power than a hard drive. I will not improve performance of a program; however it will make the laptop feel like it operates a little more smoothly.
An i5 would be better than an i3 because of Turbo Boost which is basically is an automatic overclock as long as the CPU itself is not overheating. Only the i7 "QM" models are quad core CPUs so if you are going to go for an i7 CPU in a laptop, then you want a "QM" model rather than a "M" which is merely a faster dual core CPU than the i5.
Depending on the size of the photohop files you will want at least 4GB of RAM. 8GB would be what I generally recommend for photoshop users (without knowing anything else). 16GB of RAM would be good if you work with very large size files.