Just for curiosity, which camera manufaturer uses .raw format? I'm not familiar with that particular RAW format but, all RAW formats are very lightly compressed or not compressed at all and take a lot of space so, you would be better exporting those images to a more compressed file format, unless you have an enormous amount of RAM memory for training your model..
Thanks for your response! It is an instrument taken picture and then cropped to reduce size. Python reads them without any problem but I do not how to read into R.
If a python library can read the file then you can use it within your R workflow using the reticulate package for importing the python library into R, for example I use this python library for generating 1D barcodes and later I render this images in html tables using rmarkdown.
library(reticulate)
use_python("/usr/bin/python3.5")
barcode <- import("barcode")
name <- barcode$generate('EAN14', '77751493001181', output='barcode_img')