SVGs not well supported even though listed in "accepted file types"

[keevan]

Uploading an SVG causes errors to appear as below. We've tried updating web_image to a fixed list of supported types, but this didn't work in Totara 16 and broke image uploads.

Example test using PNG

: Undefined property: stdClass::$heightres in
/var/www/site/server/blocks/carousel/block_carousel.php
on line
147

Notice
: Undefined property: stdClass::$widthres in
/var/www/site/server/blocks/carousel/block_carousel.php
on line
147

Notice
: Undefined property: stdClass::$heightres in
/var/www/site/server/blocks/carousel/block_carousel.php
on line
172

Notice
: Undefined property: stdClass::$widthres in
/var/www/site/server/blocks/carousel/block_carousel.php
on line
175

Notice
: Undefined property: stdClass::$heightres in
/var/www/site/server/blocks/carousel/block_carousel.php
on line
175

Warning
: Division by zero in
/var/www/site/server/blocks/carousel/block_carousel.php
on line
175

Notice
: Undefined property: stdClass::$heightres in
/var/www/site/server/blocks/carousel/block_carousel.php
on line
147

Notice
: Undefined property: stdClass::$widthres in
/var/www/site/server/blocks/carousel/block_carousel.php
on line
147

Notice
: Undefined property: stdClass::$heightres in
/var/www/site/server/blocks/carousel/block_carousel.php
on line
172

Notice
: Undefined property: stdClass::$widthres in
/var/www/site/server/blocks/carousel/block_carousel.php
on line
175

Notice
: Undefined property: stdClass::$heightres in
/var/www/site/server/blocks/carousel/block_carousel.php
on line
175

Warning
: Division by zero in
/var/www/site/server/blocks/carousel/block_carousel.php
on line
175

Notice
: Undefined property: stdClass::$heightres in
/var/www/site/server/blocks/carousel/block_carousel.php
on line
147

Notice
: Undefined property: stdClass::$widthres in
/var/www/site/server/blocks/carousel/block_carousel.php
on line
147

Notice
: Undefined property: stdClass::$heightres in
/var/www/site/server/blocks/carousel/block_carousel.php
on line
172

Notice
: Undefined property: stdClass::$widthres in
/var/www/site/server/blocks/carousel/block_carousel.php
on line
175

Notice
: Undefined property: stdClass::$heightres in
/var/www/site/server/blocks/carousel/block_carousel.php
on line
175

Warning
: Division by zero in
/var/www/site/server/blocks/carousel/block_carousel.php
on line
175