Can we change Image Resolution in Blender ?

Hi all,
I am not really confortable with textures and still at the bottom of Blender learning curve as I usually say.
Everything is working fine in my Blender files but my texture images are quite large (2Mo each) and I have a lot of them.
I have tried to decrease the ‘weight’ down to 0.2 Mo in Photoshop for some of them and this is fine for me.

Now my question: do I really have to go to Photoshop and import back to Blender or can I tell Blender to decrease the resolution of my images??
Thank you all.

as far as i know you can’t.
Resizing them in photoshop is definetely not a bad idea as long as you save it as a second version. Then you can change between low-res and high-res texture easily when needed

Textures will always be imported with the resolution they’re saved in. You might be able to alter the resolution in the UV editor, but I don’t think that would help performance.

Thank you Avagantamo and hris for your replies.

I am surprised by one feature regarding texture files in Blender: when I import, say a 1 Mo texture file (.jpg), UV edit it to a mesh etc…and then export the mesh as a .dae format, the exported texture file is 2 Mo.
How come ?
Is there any option I should unchecke to avoid this ?

Thank you.

You can allways change the compression of the file (when the format accepts it)… For a PNG it’e even better as you don’t have detail loss. This can turn a 2Mb png file, into a 300k file, depending on the image.
For scaling, converting, etc, you can allways use compositor to do it! just use the image as the input, and render with the desired resolution, format, whatever.

That sounds interesting. But where is the compression panel ?
Thanks

The compression is right below the button where you choose the output format. In the ‘Properties’ panel, ‘Render’ tab, it will be in ‘Output’ subpanel.
In the ‘File Browser’ panel, it will be on the left side, in the ‘Save As Image’ subpanel.

Thanks Secrop
In the Property panel, it seems to apply for all textures in the Blender file, right ? If so, is there a way to deal with a specific texture ?
I have tried to export (COLLADA format) with various ‘Quality’ settings ranging from 10% to 90% (JPEG) but the exported texture file weights the same…
Are we talking about the same thing ?


Thats for the render part only, when for example your are using the compositor to place an image as an input, and scale it to a new resolution.

To save your textures with just another compression, go into Image editor, select your Texture and press F3… Then, on the left, in a similar panel, you can change the quality of the new file.

Why isn’t there a Node for this? For simple rescaling of resolution this should be possible within the application, surely?!

Why do you need a node for this? The node system is for JIT operations, and if you want to rescale an image, you probably don’t want to do it everytime you run the nodetree.

And it is indeed possible!!! Blender let’s you change the image instance resolution (instance here means that without saving it to a new file, the rescaled image will be lost when you close the session).

width = 400
height = 300
bpy.data.images['Your Image'].scale(width, height)

Thanks for explaining that this is possible. I’ll research elsewhere on how to implement it.