pamscale — Scale a Netpbm image. More information: <https://netpbm.sourceforge.net/doc/pamscale.html>.

Scale an image such that the result has the specified dimensions

pamscale {{[-wid|-width]}} {{width}} {{[-h|-height]}} {{height}} {{path/to/input.pam}} > {{path/to/output.pam}}

Scale an image such that the result has the specified width, keeping the aspect ratio

pamscale {{[-wid|-width]}} {{width}} {{path/to/input.pam}} > {{path/to/output.pam}}

Scale an image such that its width and height is changed by the specified factors

pamscale {{[-xsc|-xscale]}} {{x_factor}} {{[-ysc|-yscale]}} {{y_factor}} {{path/to/input.pam}} > {{path/to/output.pam}}

Scale an image such that it fits into the specified bounding box while preserving its aspect ratio

pamscale -xyfit {{bbox_width}} {{bbox_height}} {{path/to/input.pam}} > {{path/to/output.pam}}

Scale an image such that it completely fills the specified box while preserving its aspect ratio

pamscale -xyfill {{box_width}} {{box_height}} {{path/to/input.pam}} > {{path/to/output.pam}}