If your images look great in Photoshop, but are of lower quality in ID, the first thing is to make sure you are looking at the best possible preview. Go to View > Display Performance and choose High Quality Display. While you are there, also take note if Allow Object Level Display Settings is checked. If it is it’s also possible the image itself is set to Typical display. You can select the image and check the context menu for display settings, or clear them from the View menu. If you don’t see an improvement, go to the application preferences (InDesign > Preferences on Mac, Edit > Preferences on PC) and check the Display Performance section to be sure the quality settings for High Quality Display are set to the maximum.
Once you are looking at the best possible preview, check the image resolution. Select the image and open the Info panel (Window > Info). You should see two listings for resolution, “Actual” and “Effective.” The one you care about is effective. If the image is low resolution to start with, like a screen capture, or the image has been scaled up significantly, you should not expect to see a beautiful smooth rendering.
Finally, remember that InDesign is showing you a preview, not the actual image. If the entire image were embedded in your ID file it wouldn’t take it long to become unworkably large, so You are shown a smaller jpeg preview to help you with positioning and color judgments, but it is still JUST A PREVIEW. Make quality decisions based on the final output (print or PDF).
If your images seem to degrade when printing, go to the Graphics panel in the Print dialog, and in the Images section set the “Send Data:” dropdown to “All.” If they degrade in your exported PDF, check the compression settings in the Export dialog and be sure you are using an appropriate type and level of compression for the intended purpose.