Never Work on Your Original Digital ImagesWriten by Eric Hartwell
Keep your original images intact.
Many people will want to work on their mages using an image-editing program. This could include cropping, changing the levels, hues and saturation. You might even be doing more advanced image manipulations.
Perhaps you are saving the images either before or after image manipulations.
The golden rule is: never work on the original. Always make a copy and work on that.
Why should you do this?
Because, if the original is changed then you may very well lose some of the data within it. For example, compressing an image will mean a loss of data which will result in some loss of quality of the image.
If you compressed the original then it is lost forever. If a copy of the original was compressed, you always have the original file to hand.
You can open the original, work on it and then use save as to save it as another file with a different name (if your original was, for example cat.jpg then you could save it as cat1.jpg).
If you do this then you will always be able to retain the data in the original image. You never know when you might need this for example when performing a new manipulation on the image.
Eric Hartwell runs the photography resource site http://www.theshutter.co.uk and the associated discussion forums as well as the regular weblog at http://thephotographysite.blogspot.com