This image shows some kind of formula that could be converted to TeX . Storing formulas as images makes it harder to change them. TeX also helps making sure that they all use the same font and size.
A replacement has been proposed:

${\displaystyle {\ce {H-{\overset {\displaystyle H \atop |}{\underset {| \atop \displaystyle H}{C}}}-{\overset {\displaystyle H \atop |}{\underset {| \atop \displaystyle H}{C}}}-{\overset {\displaystyle H \atop |}{\underset {| \atop \displaystyle H}{C}}}-{\overset {\displaystyle H \atop |}{\underset {| \atop \displaystyle H}{C}}}-{\overset {\displaystyle H \atop |}{\underset {| \atop \displaystyle H}{C}}}-{\overset {\displaystyle H \atop |}{\underset {| \atop \displaystyle H}{C}}}-H}}}$

In your article, replace the image with:

<chem>H-
\overset{\displaystyle H \atop | }{\underset{ | \atop \displaystyle H}{C} }-
\overset{\displaystyle H \atop | }{\underset{ | \atop \displaystyle H}{C} }-
\overset{\displaystyle H \atop | }{\underset{ | \atop \displaystyle H}{C} }-
\overset{\displaystyle H \atop | }{\underset{ | \atop \displaystyle H}{C} }-
\overset{\displaystyle H \atop | }{\underset{ | \atop \displaystyle H}{C} }-
\overset{\displaystyle H \atop | }{\underset{ | \atop \displaystyle H}{C} }-
H</chem>