Current issue with resaving the JPEGs is that the content of the images stays in the same 8x8 blocks and are compressed again in approximately the same way.
To solve this, pad the image at the top and left sides by random values between 0 and 8 pixels to shift the image content into different 8x8 blocks. Then save the JPEG and crop out the padding. Could pad all edges and use a solid color to make it bleed into the image, or pad it with a reflection of the image.
A little random resizing can also break up the image between resaves.
Current issue with resaving the JPEGs is that the content of the images stays in the same 8x8 blocks and are compressed again in approximately the same way.
To solve this, pad the image at the top and left sides by random values between 0 and 8 pixels to shift the image content into different 8x8 blocks. Then save the JPEG and crop out the padding. Could pad all edges and use a solid color to make it bleed into the image, or pad it with a reflection of the image.
A little random resizing can also break up the image between resaves.