Images being distorted

Hi helpful people,

we are displaying some png images, which were created by a graphic designer. The height of the images is exact and very import to our experiment. When PscyhoPy displays the images they are being distorted and not showing at the same quality as they are shown in other programmes such as Word or PowerPoint.

We are using cm as our units and are setting the height and width to the exact dimensions they were created with in photoshop. Can anyone offer any insight into this issue?

Alternatively, if someone could offer any advice on how to show the images with their default dimensions that would be great. If we specify size=None then the image is shown much too large.

TIA :slight_smile:

What file format? PNG? JPG? Some kind of vector format?

I suspect, that PsychoPy probably does not know your screen dimensions and so cannot use “cm” appropriately. Also, I suspect that the image in its real size is in fact bigger than the screen. What you could do is take the pixel width and height of the image (e.g. 1920 by 1080), use pixel units, and input $[1920 * x, 1080 * x] into the “size” field. x would then be the scaling factor that you could choose to make the image fit your screen.

The images are pngs.

Thanks so much for your response. The images are actually displaying in the correct size. They are just distorted. We have set up monitor center and the cm seem to be working well.

Ah, by “distorted” you just mean that the quality is lower, not that the dimensions are off?

You may have more luck using TIFFs or another uncompressed raster format, if the issue is some kind of image compression. Otherwise it sounds like changing the units has solved things.