When I record actions, I put in the pixel size I want it to save as (1000x1000) for web export. For some reason, it will only replay this action and resize based on a scaling percentage. Is there a way to fix this without having to edit scripts? I tried changing preferences for units to pixels, but that didn't work. Please help!
When you record your action, before exporting click Image > Duplicate. Rescale the duplicate using Image > Image Size. Export the duplicate using File > Export > Save for Web (Legacy). Then close the duplicate without saving it.
This allows you to basically create a temporary document for rescaling purposes, without affecting the original image.
Record with "Image Size" function used. After recording the action, in action panel, click "Action 1" -> Image Size(Double Click) -> set pixel or percentage or ... then run again
It doesn't look like this can be done using "Save for web ... " in an action. However, Minu J is correct - you can use Image Size (under the Image menu) for this: