Yes. A few commonly recommended resources are:

• DPReview: Their reviews are very detailed and usually include controlled sample images and side-by-side comparisons, which can help you judge image quality across models.
• DxOMark: They publish lab-style measurements for camera sensors and camera/lens combinations, aimed at objective image-quality comparison.
• Flickr: Not a lab test site, but browsing images by camera model can show real-world results from actual users.
• Snapsort: Useful for broad camera comparisons, though it’s more of a buying comparison tool than a pure image-quality testing resource.

That said, measured image quality is only part of choosing a camera. Handling, lens options, autofocus, low-light needs, zoom range, and the type of photography you do often matter just as much as lab results.