Thank you for your post.
When converting the PDF file to JPG, make sure you save as highest quality (although it shouldn't matter). Then, just to be sure, since you have Photoshop, open the JPG in Photoshop. How does it appear here? Check the Image Size and the quality (72 DPI minimum - 300 DPI recommended). Make any adjustments and save again as JPG.
In FileMaker Pro, make the Layout large enough, pull down the Insert menu and select "Picture". Select your JPG file, and it should appear properly.
If you are still having difficulty, please let me know.