This page explains the graphical standards used for images of Xovimat cards on this site. Of course there are many artistic alternatives, some of which will likely generate cards that are easier to use and more attractive to look at.
The template used in producing the jpeg images is shown below; this template is here rendered in the form of an uncompressed jpeg. The pdf images are constructed according to the same design, except with a higher resolution which allows a more nuanced font.
All of the card illustrations assume that each card is rectangular (but with rounded corners), and has a height-to-width ratio of 1.4, or equivalently 7 to 5. If the cards are 3.5 inches high and 2.5 inches wide, as in the American poker and pinochle standard, the small boxes in the illustration below measure one-twelfth of an inch along each edge. Only a tiny adjustment is necessary to implement ISO size B8, which is 88 millimeters by 62 millimeters.
The drawings of cards assume margins and gutters of one-fourth inch for the pdfs, and 12 pixels for the jpegs. Many of the illustrations show several cards, and the table below gives the dimensions in of those multi-card images in inches (for pdfs), and in pixels (for jpegs):
The diagram above does not show the various fields in their true colors, alterations being necessary to render the grid clearly. In the table below are the settings used to generate the images; they are the same for the jpegs and pdfs. The colors come from a built-in palette of AppleWorks ("240 Grays & 16 Colors"); numerically, each component ranges from 0 to 255.