I am not sure why sometimes this error is shown when using images. Initially, I thought it is happening because of using JFIF standard jpg images vs EXIF standard jpg images but now I found a case that also happens for EXIF standard jpg images. How can I debug this problem and how can that be solved? I am using PyTorch 1.8.1.
(phosa) [jalal@goku phosa]$ file input/input/bat* | grep -i exif
input/input/bat5.jpg:  JPEG image data, EXIF standard
(phosa) [jalal@goku phosa]$ python demo.py --filename input/input/bat5.jpg --class_name bat
2021-03-31 20:26:59,384 INFO     Calling with args: Namespace(class_name='bat', filename='input/input/bat5.jpg', lw_collision=None, lw_depth=None, lw_inter=None, lw_inter_part=None, lw_scale=None, lw_scale_person=None, lw_sil=None, mesh_index=0, output_dir='output')
2021-03-31 20:27:02,203 INFO     Loading checkpoint from detectron2://PointRend/InstanceSegmentation/pointrend_rcnn_R_50_FPN_3x_coco/164955410/model_final_3c3198.pkl
2021-03-31 20:27:02,213 INFO     URL https://dl.fbaipublicfiles.com/detectron2/PointRend/InstanceSegmentation/pointrend_rcnn_R_50_FPN_3x_coco/164955410/model_final_3c3198.pkl cached in /home/grad3/jalal/.torch/fvcore_cache/detectron2/PointRend/InstanceSegmentation/pointrend_rcnn_R_50_FPN_3x_coco/164955410/model_final_3c3198.pkl
2021-03-31 20:27:02,300 INFO     Reading a file from 'Detectron2 Model Zoo'
WARNING: You are using a SMPL model, with only 10 shape coefficients.
class_name:  bat
Traceback (most recent call last):
  File "demo.py", line 145, in <module>
    main(get_args())
  File "demo.py", line 120, in main
    object_parameters = find_optimal_poses(
  File "/scratch3/research/code/phosa/phosa/pose_optimization.py", line 426, in find_optimal_poses
    object_parameters[k] = torch.stack(v)
RuntimeError: stack expects a non-empty TensorList

an image that breaks the code:
(phosa) [jalal@goku phosa]$ identify -verbose input/input/bat5.jpg
Image: input/input/bat5.jpg
  Format: JPEG (Joint Photographic Experts Group JFIF format)
  Mime type: image/jpeg
  Class: DirectClass
  Geometry: 1417x957+0+0
  Resolution: 72x72
  Print size: 19.6806x13.2917
  Units: PixelsPerInch
  Colorspace: sRGB
  Type: TrueColor
  Base type: Undefined
  Endianess: Undefined
  Depth: 8-bit
  Channel depth:
    red: 8-bit
    green: 8-bit
    blue: 8-bit
  Channel statistics:
    Pixels: 1356069
    Red:
      min: 4  (0.0156863)
      max: 246 (0.964706)
      mean: 121.121 (0.474984)
      standard deviation: 65.4112 (0.256514)
      kurtosis: -1.42305
      skewness: -0.279998
      entropy: 0.952832
    Green:
      min: 4  (0.0156863)
      max: 248 (0.972549)
      mean: 123.048 (0.482542)
      standard deviation: 63.9564 (0.25081)
      kurtosis: -1.37041
      skewness: -0.31156
      entropy: 0.955039
    Blue:
      min: 4  (0.0156863)
      max: 247 (0.968627)
      mean: 125.684 (0.492879)
      standard deviation: 64.8382 (0.254268)
      kurtosis: -1.35544
      skewness: -0.330874
      entropy: 0.957843
  Image statistics:
    Overall:
      min: 4  (0.0156863)
      max: 248 (0.972549)
      mean: 123.284 (0.483468)
      standard deviation: 64.7353 (0.253864)
      kurtosis: -1.38286
      skewness: -0.307323
      entropy: 0.955238
  Rendering intent: Perceptual
  Gamma: 0.454545
  Chromaticity:
    red primary: (0.64,0.33)
    green primary: (0.3,0.6)
    blue primary: (0.15,0.06)
    white point: (0.3127,0.329)
  Background color: white
  Border color: srgb(223,223,223)
  Matte color: grey74
  Transparent color: black
  Interlace: None
  Intensity: Undefined
  Compose: Over
  Page geometry: 1417x957+0+0
  Dispose: Undefined
  Iterations: 0
  Compression: JPEG
  Quality: 94
  Orientation: Undefined
  Properties:
    date:create: 2021-04-01T00:02:56+00:00
    date:modify: 2021-04-01T00:01:01+00:00
    exif:DateTime: 2019-05-08T22:34:50+02:00
    exif:ExifOffset: 156
    exif:ExifVersion: 48, 50, 50, 48
    exif:PixelXDimension: 1417
    exif:PixelYDimension: 957
    exif:ResolutionUnit: 2
    exif:Software: Adobe Photoshop CS6 Windows
    exif:XResolution: 72/1
    exif:YResolution: 72/1
    jpeg:colorspace: 2
    jpeg:sampling-factor: 1x1,1x1,1x1
    signature: b933305114f74f66bd8c0430f6689843f3287008be2e0663974091322a869040
  Profiles:
    Profile-app12: 15 bytes
    Profile-exif: 210 bytes
    Profile-xmp: 960 bytes
  Artifacts:
    filename: input/input/bat5.jpg
    verbose: true
  Tainted: False
  Filesize: 256664B
  Number pixels: 1.35607M
  Pixels per second: 39.5923MB
  User time: 0.030u
  Elapsed time: 0:01.034
  Version: ImageMagick 6.9.10-68 Q16 x86_64 2021-02-24 https://imagemagick.org

an image that will work:
(phosa) [jalal@goku phosa]$ identify -verbose input/bat_sidehold.jpg 
Image: input/bat_sidehold.jpg
  Format: JPEG (Joint Photographic Experts Group JFIF format)
  Mime type: image/jpeg
  Class: DirectClass
  Geometry: 1156x1600+0+0
  Resolution: 72x72
  Print size: 16.0556x22.2222
  Units: PixelsPerInch
  Colorspace: sRGB
  Type: TrueColor
  Base type: Undefined
  Endianess: Undefined
  Depth: 8-bit
  Channel depth:
    red: 8-bit
    green: 8-bit
    blue: 8-bit
  Channel statistics:
    Pixels: 1849600
    Red:
      min: 0  (0)
      max: 255 (1)
      mean: 226.177 (0.886968)
      standard deviation: 64.3149 (0.252215)
      kurtosis: 5.41792
      skewness: -2.58614
      entropy: 0.409396
    Green:
      min: 0  (0)
      max: 255 (1)
      mean: 219.381 (0.860319)
      standard deviation: 57.0324 (0.223657)
      kurtosis: 0.586459
      skewness: -1.36916
      entropy: 0.443656
    Blue:
      min: 0  (0)
      max: 255 (1)
      mean: 220.606 (0.86512)
      standard deviation: 54.885 (0.215235)
      kurtosis: 0.68018
      skewness: -1.36917
      entropy: 0.442032
  Image statistics:
    Overall:
      min: 0  (0)
      max: 255 (1)
      mean: 222.055 (0.870803)
      standard deviation: 58.7441 (0.230369)
      kurtosis: 2.75662
      skewness: -1.88089
      entropy: 0.431695
  Rendering intent: Perceptual
  Gamma: 0.454545
  Chromaticity:
    red primary: (0.64,0.33)
    green primary: (0.3,0.6)
    blue primary: (0.15,0.06)
    white point: (0.3127,0.329)
  Background color: white
  Border color: srgb(223,223,223)
  Matte color: grey74
  Transparent color: black
  Interlace: JPEG
  Intensity: Undefined
  Compose: Over
  Page geometry: 1156x1600+0+0
  Dispose: Undefined
  Iterations: 0
  Compression: JPEG
  Quality: 65
  Orientation: Undefined
  Properties:
    date:create: 2021-03-26T05:48:14+00:00
    date:modify: 2021-03-26T05:48:14+00:00
    exif:Copyright: (c) Zhagunov | Dreamstime.com
    exif:ResolutionUnit: 2
    exif:XResolution: 72/1
    exif:YCbCrPositioning: 1
    exif:YResolution: 72/1
    jpeg:colorspace: 2
    jpeg:sampling-factor: 2x2,1x1,1x1
    signature: c1017a4d64ee13044fd81942a442cbaf6c28e42c61282ed3ab376d3dd92fd3c1
    xmpRights:WebStatement: https://www.dreamstime.com/about-stock-image-licenses
  Profiles:
    Profile-8bim: 54 bytes
    Profile-exif: 126 bytes
    Profile-iptc: 41 bytes
      Copyright String[2,116]: (c) Zhagunov | Dreamstime.com
      unknown[2,0]: 
    Profile-xmp: 3158 bytes
  Artifacts:
    filename: input/bat_sidehold.jpg
    verbose: true
  Tainted: False
  Filesize: 96559B
  Number pixels: 1849600
  Pixels per second: 35.8514MB
  User time: 0.050u
  Elapsed time: 0:01.051
  Version: ImageMagick 6.9.10-68 Q16 x86_64 2021-02-24 https://imagemagick.org