Use a more sane SVG.

res/img/icons-room-add.svg

@@ -1,71 +1,9 @@
-<?xml version="1.0" encoding="UTF-8" standalone="no"?>
-<svg
-   xmlns:dc="http://purl.org/dc/elements/1.1/"
-   xmlns:cc="http://creativecommons.org/ns#"
-   xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
-   xmlns:svg="http://www.w3.org/2000/svg"
-   xmlns="http://www.w3.org/2000/svg"
-   xmlns:sodipodi="http://sodipodi.sourceforge.net/DTD/sodipodi-0.dtd"
-   xmlns:inkscape="http://www.inkscape.org/namespaces/inkscape"
-   width="11.521363"
-   height="11.521363"
-   viewBox="0 0 11.521363 11.521363"
-   version="1.1"
-   id="svg4"
-   sodipodi:docname="icons-room-add.svg"
-   style="fill:none"
-   inkscape:version="0.92.3 (2405546, 2018-03-11)">
-  <metadata
-     id="metadata10">
-    <rdf:RDF>
-      <cc:Work
-         rdf:about="">
-        <dc:format>image/svg+xml</dc:format>
-        <dc:type
-           rdf:resource="http://purl.org/dc/dcmitype/StillImage" />
-        <dc:title></dc:title>
-      </cc:Work>
-    </rdf:RDF>
-  </metadata>
-  <defs
-     id="defs8" />
-  <sodipodi:namedview
-     pagecolor="#ffffff"
-     bordercolor="#666666"
-     borderopacity="1"
-     objecttolerance="10"
-     gridtolerance="10"
-     guidetolerance="10"
-     inkscape:pageopacity="0"
-     inkscape:pageshadow="2"
-     inkscape:window-width="1586"
-     inkscape:window-height="988"
-     id="namedview6"
-     showgrid="false"
-     fit-margin-top="2"
-     fit-margin-left="2"
-     fit-margin-right="2"
-     fit-margin-bottom="2"
-     inkscape:zoom="29.5"
-     inkscape:cx="5.8284785"
-     inkscape:cy="5.7606831"
-     inkscape:window-x="0"
-     inkscape:window-y="27"
-     inkscape:window-maximized="0"
-     inkscape:current-layer="svg4" />
-  <path
-     d="m 5.7606819,2.7606819 v 6"
-     id="path2"
-     inkscape:connector-curvature="0"
-     style="stroke:#ffffff;stroke-width:1.5;stroke-linecap:round" />
-  <g
-     style="fill:none"
-     id="g876"
-     transform="translate(1.7606819,4.7606819)">
-    <path
-       id="path865"
-       d="M 7,1 H 1"
-       inkscape:connector-curvature="0"
-       style="stroke:#ffffff;stroke-width:1.5;stroke-linecap:round" />
+
+<svg width="8px" height="8px" viewBox="0 0 8 8" version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
+    <g id="Design" stroke="none" stroke-width="1.6" fill="none" fill-rule="evenodd" stroke-linecap="round">
+        <g id="Add" transform="translate(1.000000, 1.000000)" fill-rule="nonzero" stroke="#FFFFFF">
+            <path d="M3,0 L3,6" id="Stroke H"></path>
+            <path d="M3,0 L3,6" id="Stroke V" transform="translate(3.000000, 3.000000) rotate(90.000000) translate(-3.000000, -3.000000) "></path>
+        </g>
     </g>
 </svg>