Can I change the compression ratio of a JPEG image on travel.state.gov?

We can devise two ways to do this (1) by editing the image, or (2) by editing the JavaScript code.

How it works

Looking at the code, you can see how it's calculated from the definition of

function getCompressionRatio(e, t) {
    return 3 * e.naturalWidth * e.naturalHeight / t
}

And the call site,

var e = getCompressionRatio(image, imageNumBytes);

So in the definition e is image and t is imageNumBytes. This is the assumption that the raw image is 3 bytes-per-pixel (TrueColor).

function getCompressionRatio(image, t) {
    return 3 * image.naturalWidth * image.naturalHeight / imageNumBytes
}

Our options

Editing the image: In order to get a lower "compression ratio" for your image you need only lower the numerator ( 3 * image.naturalWidth * image.naturalHeight ) or raise the denominator by making imageNumBytes (image size) bigger.

Editing the JavaScript code: Alternatively this error is rendered here,

if (MAX_COMPRESSION_RATIO < e)
    setUI(UIModeEnum.INIT),
    setMessageDialog("Your photo has been rejected for the following reason(s):", [{
        description: "Image is overly compressed. Please use a compression ratio that is less than 20:1"
    }]),
    showControls(!0, ["divMessages"]);

In Chrome you can open up the developer console (Ctrl + Shift + J) and run,