Use of a software license for media should be discouraged in general but it really depends on how the software license is written. Considerations about specific licenses follow.
Section 0 of the GNU GPL 3.0 license contains a definition of "The Program":
"The Program" refers to any copyrightable work licensed under this
and Section 1 defines the "source code":
The "source code" for a work means the preferred form of the work
for making modifications to it.
This explains why the GNU FAQ clearly states that the license can be used for something other than software:
Can I use the GPL for something other than software?
You can apply the GPL to any kind of work, as long as it is clear what constitutes the “source code” for the work. The GPL defines this as the preferred form of the work for making changes in it.
In the case of an SVG image, or a PNG image having vectorial source, this license choice can make a lot of sense.
What I said for the GPL is even truer for the Apache 2.0 license. Indeed, it contains the following definitions:
"Source" form shall mean the preferred form for making modifications,
including but not limited to software source code, documentation
source, and configuration files.
"Object" form shall mean any form resulting from mechanical
transformation or translation of a Source form, including but
not limited to compiled object code, generated documentation,
and conversions to other media types.
"Work" shall mean the work of authorship, whether in Source or
Object form, made available under the License, as indicated by a
copyright notice that is included in or attached to the work
(an example is provided in the Appendix below).
Therefore the Apache license is specifically designed to be applicable beyond software (other media types are even mentioned) whereas the choice of terms throughout the preamble and the rest of the GPL clearly demonstrates that the license was designed for software even though it can still be applied to some other works.
On the contrary, the MIT license defines the "Software" as:
a copy of this software and associated documentation files
Thus the MIT license would lose its meaning completely in case it was applied to media which isn't documentation.
The BSD licenses (2 and 3-clause) do not contain any definitions but mention "source code", "binary form" and "THIS SOFTWARE". Thus, similarly to the MIT license, it should not be used for anything else than software.
Finally if a software contains media, it makes sense to license the whole software, including media, under a software license, but in this case authors would be well advised to dual license the media alone under a Creative Commons license.