The yellow triangle icon alerts you any time the pixel dimension of the image is smaller than the pixel dimension it will be exported.
Resolution and how all of these factors relate to each other is one of the most confusing and misunderstood aspects of digital photography.
First of all, there are three factors that control resolution. Pixels, Size and DPI/PPI.
We like using pixels because it's an absolute value. 3,000 pixels is exactly that and will never change.
Let's create a new image in Photoshop, say 6" x 4" @ 300 PPI. That image is also 2400 x 1200 pixels.
If you resize the image (and turn off Resample) the width, height and resolution will all change, but the pixels won't.
For example, if you change the resolution to 150 PPI, the width changes to 16 and the height changes to 8, but the pixels remain the same!
So, when you set up your album in Fundy Designer, you are choosing the size and our software will do the rest based on each album companys' specifications. If you are using photos that are not high enough resolution, you will see the warning triangle, along with the information you were referring to. It's basically saying this is what the image size needs to be and here is what your image size is.
If this is a big difference, we advise resizing the photos in Photoshop or Lightroom. Even if you captured as a small RAW file, you can change your export settings and export a higher resolution image. You can then resync in our software to the higher resolution images.
The other alternatives are to open each image (using the external editor button) into Photoshop and upsize the images, then save and close. Finally, you can simply ignore the warning and our software will automatically resize the images on export. The best quality will be to export higher resolution images from your RAW file, the next best quality is to resize them in Photoshop and the final is letting our software do it for you.
If none of these options work for you, we would recommend making your images smaller on your spreads (i.e. not full page bleeds) or choosing a smaller album that would not require such large photos.
Think of it as a YIELD sign, not a STOP sign. Just be sure to double check the final export before submitting for printing.
Here is a video that explains this further.