unwanted compression of custom header image in Vortex

Hello,

I’m outputting my header image at the dimensions specified (little or no cropping necessary). I’ve output it a bunch of different times as either a png or jpeg from both Photoshop and Illustrator (at 72 dpi, with raster effects also at 72 dpi).

While I recognize the difficulties in getting a serif font to look good in lo rez outputs from either of these programs, I am able to get the png versions to a point where they’re at least acceptable, but when I upload them as the Vorex header, further compression appears to happen so that the text in particular looks like dreck.

I’ve had better luck in the past with paid themes from Themeforest, but am wondering if this problem inherent to Vortex, WordPress or both?

Can anyone help me here? It’s not the end of the world if I have to install a different theme, but want to find out as much as I can before doing this.

Thanks.