kpiela wrote:
okay... not sure about compression level. I just did a "save as" "jpeg". The raw image had about 26MB to begin with. I worked on the TIF image then "saved as" to a jpeg. Does this make sense? I have just started working with raw images so i am at an entry level of understanding it all1
Ok, ignore the fact that you were working with a raw file, the size of the jpeg has nothing to do with that.
When you save a jpeg file the app you're using should have an option somewhere to set the amount of compression being used to control quality. Try saving your file again but this time check what the quality setting is at. Try saving at the highest quality and see if the new file is any bigger.
Of course, if your image had a lot of plain areas without any detail the jpeg will be able to compress it down quite small even on a high quality setting. In simple terms jpeg makes files smaller by re-using bits of data where it can. Imagine just a plain white image. A tif stores information for every pixel, the jpeg would analyze the image and only store one bit of white and then "reference" it for everywhere else. Note this is a simplification of what jpeg does but gives you an idea of why, in some situations, the files can get so small.