Image tools for android (blur,crop,scale)

I often have a lot of different images ,with custom sizes. In this case I am just do this in xml or in code, for instance using scaleType.

But it sometimes there are a lot of images,so I need to scale each image. It would be better if to do this at once.

Maybe there are some good online tools or applications suitable for this.

The most desirable feature is to save proportions and scale image according to android screen size and phones(diagonal, ASPECT ratio).

For example I have large image (1920x1080) and I need to scale it according screen aspect ratio for all screens,such image resolution allows to use on each device. So maybe there are some good tools for this purpose to work with multiple images at once.

Thanks in advance.