You need to be much more specific. What version of AE? What system? What type of JPEG? Does it use specific color profiles? Have you checked that it is actually intact and not damaged?
When you answer Mylenium's question about what version of After Effects you are using, please specify the version number exactly like "184.108.40.206" and not like "CC".
Also, have you scaled any of your layers up to a large amount?
Have you applied any effects to them? If so, what have you applied?
I created a new composition to alleviate the work and settle interest problem. Thank you for your response