I took pictures with a camera I have not used in years. The pictures appear to have vertical and horizontal pixel lines throughout. What is the cause and how can I remove them? I have no photo editing experience but downloaded Topaz DeNoise and that is not helping. Can I save these pictures and what is the issue with my camera? It's a Canon EOS T3. These are my Thanksgiving family pictures and I would love to save them.
You note that the pictures are CR2 images. These are Canon RAW files — they are not, in that state, usable for sharing and printing and so on. You need software to convert them. The most popular such software is Adobe Lightroom, but you can also download Canon Digital Photo Professional for free — or use open source software like Rawtherapee.
The key thing here is that the pattern in your picture looks very, very much like an artifact from demosaicing — part of the process of converting the sensor data stored in the RAW CR2 image into final, viewable one. Whatever software you're using to look at these images is doing it wrong. Get Canon DPP or Rawtherapee and use that to convert to JPEG, and there should be no problem.