I had seen that many beginners in this forum Posts Large size jpegs which take both time and bandwidth to open. So this is my image saving work flow. Hope it will help someone.
This is based on Photoshop.
1. after processing, save the full size if you wish.
2. Resize by pressing Ctrl+ Alt + I.
3. Add the Minimal of Border if you wish. other wise a white/black stroke will do the job from Edit menu.
4. Merge all layers by pressing Shift + Ctrl + E.
4. From file menu select save for web devices. or Press Alt + Shift + Ctrl + S.
a) Select Jpeg.
b) Quality to 60%
c) Select only Optimized.
d) Leave Pregressive, Embed Color Profile, unchecked.
e) Select Convert to sRGB.
f) Select any preview type you wish.
g) Select Metadata you want to embed with file.
h) You could resize from here also, resize if you haven't done yet.
i) Click Save.
Approx Image size you get. all sizes in px
1. 600 x 400 = 29.7-35 Kb (Standard Web size, I guess Ayaz uses this size, earlier I too post these size.)
2. 750 x 500 = 40-50 Kb (For Portraits and landscapes best size to post online of 500 px height)
3. 900 x 600 = 51-70 kb ( Macros or your shots has some fine details, Large size landscapes could also be posted this size)
4. 1050 x 700 = 65-90 kb (Detailed Macros, Mind your image will not be seen full in browser window and user has to scroll it. so avoid using this size)
5. 1200 x 800 = 80 - 120 kb (If you want to show very fine details in macros, Mind your image will not be seen full in browser window and user has to scroll it. so avoid using this size)
6. 2700 x 1800 = around 280-300 kb. ( Never Post such sizes online, your Images will be stolen)
For cropositions, Always keep the Height of Image in mind. for height more then 600px generally user has to scroll the browser widow and not able to view the image at one go.
Post Small, And save time and bandwidth.
Please feel free to correct me as this is totally my exp. and thinking.