Hi,
I’m not sure if it will ever affect the training.
I was able to get rid of the warnings by using a script to remove all exif data with the piexif library.
The script below didn’t work at first because one of the JPEG’s is actually a PNG. You can fix that with ImageMagick:
mv n02105855/n02105855_2933.JPEG n02105855/n02105855_2933.PNG
convert n02105855/n02105855_2933.PNG n02105855/n02105855_2933.JPEG
rm n02105855/n02105855_2933.PNG

Then for good measure I also converted the JPEGs that were CMYK to RGB, although I’m not sure if this makes a difference:
convert -negate -colorspace RGB n01739381/n01739381_1309.JPEG n01739381/n01739381_1309.JPEG
convert -negate -colorspace RGB n02077923/n02077923_14822.JPEG n02077923/n02077923_14822.JPEG
convert -negate -colorspace RGB n02447366/n02447366_23489.JPEG n02447366/n02447366_23489.JPEG
convert -negate -colorspace RGB n02492035/n02492035_15739.JPEG n02492035/n02492035_15739.JPEG
convert -negate -colorspace RGB n02747177/n02747177_10752.JPEG n02747177/n02747177_10752.JPEG
convert -negate -colorspace RGB n03018349/n03018349_4028.JPEG n03018349/n03018349_4028.JPEG
convert -negate -colorspace RGB n03062245/n03062245_4620.JPEG n03062245/n03062245_4620.JPEG
convert -negate -colorspace RGB n03347037/n03347037_9675.JPEG n03347037/n03347037_9675.JPEG
convert -negate -colorspace RGB n03467068/n03467068_12171.JPEG n03467068/n03467068_12171.JPEG
convert -negate -colorspace RGB n03529860/n03529860_11437.JPEG n03529860/n03529860_11437.JPEG
convert -negate -colorspace RGB n03544143/n03544143_17228.JPEG n03544143/n03544143_17228.JPEG
convert -negate -colorspace RGB n03633091/n03633091_5218.JPEG n03633091/n03633091_5218.JPEG
convert -negate -colorspace RGB n03710637/n03710637_5125.JPEG n03710637/n03710637_5125.JPEG
convert -negate -colorspace RGB n03961711/n03961711_5286.JPEG n03961711/n03961711_5286.JPEG
convert -negate -colorspace RGB n04033995/n04033995_2932.JPEG n04033995/n04033995_2932.JPEG
convert -negate -colorspace RGB n04258138/n04258138_17003.JPEG n04258138/n04258138_17003.JPEG
convert -negate -colorspace RGB n04264628/n04264628_27969.JPEG n04264628/n04264628_27969.JPEG
convert -negate -colorspace RGB n04336792/n04336792_7448.JPEG n04336792/n04336792_7448.JPEG
convert -negate -colorspace RGB n04371774/n04371774_5854.JPEG n04371774/n04371774_5854.JPEG
convert -negate -colorspace RGB n04596742/n04596742_4225.JPEG n04596742/n04596742_4225.JPEG
convert -negate -colorspace RGB n07583066/n07583066_647.JPEG n07583066/n07583066_647.JPEG
convert -negate -colorspace RGB n13037406/n13037406_4650.JPEG n13037406/n13037406_4650.JPEG

Then you can remove th EXIF data:
import glob
import piexif

nfiles = 0
for filename in glob.iglob('~/ImageNet/**/*.JPEG', recursive=True):
    nfiles = nfiles + 1
    print("About to process file %d, which is %s." % (nfiles,filename))
    piexif.remove(filename)