Thanks for all the suggestions guys - Much appreciated. I just tried out ShortPixel having paid for the 12000 images subscription. However, the compression is so much that I decided to not use it. I am not sure if it is because I am saving an already rather compressed image via photoshop only to be compressed more again but this time, it is quite blurry and don't think it gives visitors good impression of the website.
In terms of speed,prior to the compression, I was getting PageSpeed Scores of 93% and Y speed of 73%
After the compression, I am getting 96%/ 78% but I think the minor gain in % isn't enough to justify the reduction in image quality for me.
What I find strange prior to compression, the main page is 2.4mb, and after it is 1.6mb but the loading time is only down from 4.5s to 3.5s. I would have thought it would be faster.
Would you guys think the scores above is OK and will get penalized much by google or should I think of other ways to get the page speed down ?