Is Jetpack conflicting with ShortPixel? Why is that?
We added a warning in ShortPixel Image Optimization plugin because "The Speed Up Image Load Times" (formerly "Photon") from Jetpack also has an image optimization component. In some cases, this leads to the over-compression of the images (e.g. they look blurry or pixelated).
If you feel that this is your case, then you can either deactivate this component or you can use Glossy or Lossy image optimization option in ShortPixel.
If you cannot notice any over-optimization/pixelation issue while using both ShortPixel and Jetpack then it should be safe to just dismiss that warning.