Fix image abscissa when in RTL

[atomiix]

As reported in #303, if you try example_018.php, you'll see:

This fix comes from @ctadri, but then example_051.php doesn't work anymore when in RTL (by modifying lang/eng.php). However, by setting the palign parameter of the function Image() to 'C', you can make it work back.

More generally, I think it's easier to tweak a direct call to Image() to place the image where you want according to the language direction than to tweak the html to have the image aligned as you want.

[CLAassistant]

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