>>because that is what the photographer sent them to me as<<
So you were dropping them into ID without any editing at all? Were you converting to CMYK format? (as they probably originated in RGB). Did you not need to do any cropping or levels or curve adjustment or any other editing first? What about file format? Were they JPGs?
As you admit in the first post that you are new to this, a few words of advice about photos.
Most times when you receive digital photos, they are RGB JPGs. The required colour mode for print purposes is CMYK. This conversion must be done in Photoshop.
Secondly, the images are usually JPGs. The preferred (but not obligatory) format is PSDs (or TIFs, but these are somewhat redundant when using ID). This can be accomplished by saving the JPGs as PSDs in Photoshop.
Thirdly, the images may need cropping, colour correcting, lightening/darkening etc etc, as well as resizing and possibly resampling. All these functioons should be carried out in Photoshop.
The final image placed in your ID document should be cropped, edited, at 100% of the final size and at 300 dpi. You can maintain image quality in Photoshop, by looking at the information supplied under Image>Image Size. There you will find the number of pixels (width x length) in the image. You will also see the resolution. Often when a digital image is first opened in Photoshop, its resolution will default to 72dpi, but the dimensions of the image at that resolution - assuming it has been captured by a decent digital camera - can be very large. You can see the change in the dimensions of the image when it is adjusted to 300dpi, by first UNCHECKING the Resample box, and inputting 300 in the resolution box. You will then see the dimensions of the image change in the same proportion as the resolution BUT THE NUMBER OF PIXELS WILL REMAIN THE SAME. In other words, all the original pixels are still there (as will the quality) but now the pixels are closer together and so will give a sharper image when printed (but not when viewed on screen, which can only show a max of 72dpi).