I see some problems with your LoadImage() code snippet:

(1) The images list will contain only one image and it will contain bogus or a trash. The variable b is set to 1 (use bool for it), then the image is appended to the list, then it is filled by pixels and then the while cycle is exited. imageNumber should be 1 and the images list will contain the image before filling.
(2) Reading the data values is shifted. C++ fields are indexed starting from zero, therefore
Qt Code: 
  1. colors=qRgb(data.value(0),data.value(1),data.value(2));
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(supposing the data contain RGB triplets. If they are ARGB then, really, data(1), data(2), data(3) but you need to remove 4 bytes).
(3) The removeFirst() method can be really expensive. I suggest:
Qt Code: 
  1. int k = 0;
  2.  
  3. for( int i = 0; i < getHeight(); i++ )
  4. {
  5.   for( int j = 0; j < getWidth(); j++ )
  6.   {
  7.     colors=qRgb(data.value(k),data.value(k+1),data.value(k+2));
  8.     a.setPixel(j,i,colors);
  9.     k += 3;
  10.   }
  11. }
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