JPEG is a lossy image compression which can give a high compression ratio.
As far as I know, information loss takes place in JPEG during quantization.
Are there any other steps in JPEG compression where the loss takes place or can take place?
If it takes place, then where?
There are 3 aspects of JPEG compression which affect the quality and accuracy of images:
1) Loss of precision takes place during the quantization stage. Accuracy of the colors is lost in order to reduce the amount of data generated.
2) Errors are introduced during the conversion to/from the RGB/YCC color spaces.
3) Errors are introduced during the transformation to/from the frequency domain. The Discrete Cosine Transform converts pixels into the frequency domain. This conversion incurs errors in both directions.