How do I make a 1.3kb photo so it is under 290kb

You can resize/compress a photo by using the Preview application on Mac.

1. In the Preview app on your Mac, open the file you want to change.
2. Choose Tools > Adjust Size, then select “Resample image”.
3. Enter a smaller value in the Resolution field.

Reference could be found here: Resize, rotate or flip an image in Preview on Mac – Apple Support (UK)

bombameister ~ If you need to reduce photos often, consider using a simple custom shortcut to automate the process...

Screenshot of shortcut in use:

Screenshot of custom shortcut:

Reference: Shortcuts User Guide for Mac (macOS Monterey)

õ¿õ¬

You can also create a smaller file in Photos with „File > Export“. In the export dialog click the arrow tip to the right of „Photo Kind Jpeg“ to reveal the controls for the pixel size and quality. Pick smaller dimensions and a lesser JPEG quality, then export the image and use the exported image for uploading.