Texture:getPixelDimensions
Gets the width and height in pixels of the Texture.

Texture:getDimensions gets the dimensions of the texture in units scaled by the texture's DPI scale factor, rather than pixels. Use getDimensions for calculations related to drawing the texture (calculating an origin offset, for example), and getPixelDimensions only when dealing specifically with pixels, for example when using Canvas:newImageData.
pixelwidth, pixelheight = Texture:getPixelDimensions()
pixelwidth number The width of the Texture, in pixels.
pixelheight number The height of the Texture, in pixels.