Resolution Issues

I took all of my individual images using my DSLR, because of this each of my images were very large and had a very high resolution. This didn't seem like an issue until I tried to add around 30 of these images into one document. The mac I was using for the most of the project had just 1GB of RAM resulting in everything taking ages to do. Even just cropping my image took somewhere around 5 minutes. The other computer I was working on was my PC at home, I find this struggles at the best of times to do anything so asking it to open just two of my images into the same file made my life difficult, for this reason when working on my PC, I had to drastically reduce my file sizes before adding them into one document. To do this I simply opened the individual images into Photoshop and using the "image""image size" drop downs I could then resize my images to just 400pixels high to make it easier for my computer to cope. Although the need for this on the mac was less drastic I did find that reducing the size, even to 1000 pixels high, sped up the process. 
When I was making my first panorama, I made the mistake of leaving the images at full size while editing them together. Although the cropping was slow, it looked incredibly fast compared to how long it took to save. Having the images at full resolution slowed everything down, gave me huge image files and was completely unnecessary seeing as the images we needed at the end only had to be 400 pixels high. I am glad that I quickly learnt that shrinking the images make the process quicker, otherwise this project would have been a lot more stressful and a lot longer!