Given a list of monochrome images or multispectral images (example rgb, or also a z-stack of images) build a list of images of the same size by adding borders.

resizeImages.py

def ResizeImages(ImList):
        '''Find the largest width and height of images belonging to a list.
        Return a list of images of same width/height
        '''
        maxwidth=0
        maxheight=0
        if len(np.shape(ImList[0]))==3:
            components = np.shape(ImList[0])[2]
        imtype = ImList[0].dtype
        for i in range(len(ImList)):
            width=np.shape(ImList[i])[1]#width=column
            height=np.shape(ImList[i])[0]#height=line
            #print "width:height",width,":",height
            if width>maxwidth:maxwidth=width
            if height>maxheight:maxheight=height
        #print "maxwidth:maxheight",maxwidth,":",maxheight                
        NewList=[]
        for i in range(0,len(ImList)):
            width=np.shape(ImList[i])[1]
            height=np.shape(ImList[i])[0]
            
            diffw=maxwidth-width
            startw=round(diffw/2)
            diffh=maxheight-height
            starth=int(round(diffh/2))
            startw=int(round(diffw/2))
            if len(np.shape(ImList[0]))==3:
                newIm=np.zeros((maxheight,maxwidth,components), dtype=imtype)
                newIm[starth:starth+height,startw:startw+width,:]=ImList[i][:,:,:]
                NewList.append(newIm)
            if len(np.shape(ImList[0]))==2:
                newIm=np.zeros((maxheight,maxwidth), dtype=imtype)
                newIm[starth:starth+height,startw:startw+width]=ImList[i][:,:]
                NewList.append(newIm)
        return NewList