Well here is my problem, I´ve been working on an A3 size immage for a week now, and the more I worked on it the more it took time for my macbook to do some processe, at the begining it wasn´t so bad, fillter effect took more time to be done ect. But in the end, doing a brush stroke toke like 20 seconds to be done! I wasn´t shure why this was happening so I checked wich programs I was running in the same time (closed them all exept for Itunes) But it was still laggy so to speak. Once I saved I realized that my file was 500Mg big! this makes me think that this is the soucre of the lag, because the file is so HUGE... How can I reduce the size given i can´t merge the layers wich I need to work on, I can´t reduce the qualitiy of the immages I´m using because I want to print it later on. I´ve supressed every layer wich i did not need, and merged the one I could. I tryed to work on the immage with some of the layers Hidden, but for one it did not help and second I the modifications I did to the immage were hard to do because I didn´t see the wole thing. I went to the preferences as well and alowed photoshop the maximum merory possible. (Ram= 2) Sumary: did close all other programs did merge delet some layers File is in Png format. Any sugestions ?