how do i determine file types on dislabelled image files

Please use the file utility open a terminal from Apllications→Accessories→Terminal and change directory to your files directory:

using the change directory command:

cd

to get help on using cd type:

man cd

then type:

file *

sudo apt-get install imagemagick

You can now run:

identify -verbose file

It gives output like this:

Image: ./wallpaper.png
  Format: PNG (Portable Network Graphics)
  Class: DirectClass
  Geometry: 1280x1024+0+0
  Resolution: 28.34x28.34
  Print size: 45.1658x36.1327
  Units: PixelsPerCentimeter
  Type: TrueColor
  Endianess: Undefined
  Colorspace: RGB
  Depth: 8-bit
  Channel depth:
    red: 8-bit
    green: 8-bit
    blue: 8-bit
  Channel statistics:
    Red:
      min: 0 (0)
      max: 255 (1)
      mean: 226.142 (0.886833)
      standard deviation: 46.2065 (0.181202)
      kurtosis: 8.36291
      skewness: -2.7553
    Green:
      min: 0 (0)
      max: 255 (1)
      mean: 225.99 (0.886236)
      standard deviation: 45.4907 (0.178395)
      kurtosis: 7.8515
      skewness: -2.6495
    Blue:
      min: 0 (0)
      max: 255 (1)
      mean: 224.457 (0.880224)
      standard deviation: 50.3959 (0.197631)
      kurtosis: 7.77617
      skewness: -2.74471
  Image statistics:
    Overall:
      min: 0 (0)
      max: 255 (1)
      mean: 169.147 (0.663323)
      standard deviation: 105.941 (0.415454)
      kurtosis: -1.11723
      skewness: -0.848308
  Rendering intent: Undefined
  Interlace: None
  Background color: white
  Border color: rgb(223,223,223)
  Matte color: grey74
  Transparent color: black
  Compose: Over
  Page geometry: 1280x1024+0+0
  Dispose: Undefined
  Iterations: 0
  Compression: Zip
  Orientation: Undefined
  Properties:
    date:create: 2010-11-30T14:57:44+00:00
    date:modify: 2010-11-30T14:57:44+00:00
    jpeg:colorspace: 2
    jpeg:sampling-factor: 1x1,1x1,1x1
    signature: f08be9423e788eb16a505e2581a432c6d1bc85aef1a5dbea72cd1ad3b7f083d2
  Artifacts:
    verbose: true
  Tainted: False
  Filesize: 589KB
  Number pixels: 1.311M
  Pixels per second: 18.72M
  User time: 0.070u
  Elapsed time: 0:01.070
  Version: ImageMagick 6.6.2-6 2010-09-17 Q16 http://www.imagemagick.org

Neither solution worked. @ error/blo b.c/OpenBlob/2498. message received from imagemagick

What is the output of:

file imagefilename

Thanks

The reply was data. I hope that helps. thanks

Yes, the file isn't an image or is a damaged image so your OS cannot tell what it is.

thanks for trying.