Are you enlarging the image in Indesign? What PDF output options are you using?
- How do you import the image? Copy and Paste? No, don't do that. Save the image on your drive and import it via File > Place…
- What is the EFFECTIVE resolution of your image? Go to the link panel, select the image and look in the information part what the Effective Resolution in PPI of your image is.
- How does the image look like, if you select it and go to the right mouse click context menu > Display Performance > High Quality Display?
- What are your PDF export settings?
Thanks for replying. I followed what you said it's made a huge difference. I changed it to High Quality Display. Also, altered the PDF settings to - compression (JPEG Lossy), JPEG Quality (Maximum), Resolution (300). It seems to have the image a lot more clearer when I create the PDF file. Thanks for your help.