我刚刚收到以下警告：
libpng warning: iCCP: known incorrect sRGB profile
它似乎指的是Lemma2.png，即下面的图片：
这是什么意思？我该如何解决？什么是libpng？
更准确地说，以下代码：
\documentclass[a4paper]{report}
\usepackage{graphicx}
\begin{document}
\includegraphics[width=13cm]{Lemma2.png}
\end{document}
生成：
This is pdfTeX, Version 3.1415926-2.5-1.40.14 (TeX Live 2013)
restricted \write18 enabled.
entering extended mode
(./pict@[email protected]
LaTeX2e <2011/06/27>
Babel <3.9f> and hyphenation patterns for 78 languages loaded.
(/usr/local/texlive/2013/texmf-dist/tex/latex/base/report.cls
Document Class: report 2007/10/19 v1.4h Standard LaTeX document class
(/usr/local/texlive/2013/texmf-dist/tex/latex/base/size10.clo))
(/usr/local/texlive/2013/texmf-dist/tex/latex/graphics/graphicx.sty
(/usr/local/texlive/2013/texmf-dist/tex/latex/graphics/keyval.sty)
(/usr/local/texlive/2013/texmf-dist/tex/latex/graphics/graphics.sty
(/usr/local/texlive/2013/texmf-dist/tex/latex/graphics/trig.sty)
(/usr/local/texlive/2013/texmf-dist/tex/latex/latexconfig/graphics.cfg)
(/usr/local/texlive/2013/texmf-dist/tex/latex/pdftex-def/pdftex.def
(/usr/local/texlive/2013/texmf-dist/tex/generic/oberdiek/infwarerr.sty)
(/usr/local/texlive/2013/texmf-dist/tex/generic/oberdiek/ltxcmds.sty))))
No file pict@[email protected].
(/usr/local/texlive/2013/texmf-dist/tex/context/base/supp-pdf.mkii
[Loading MPS to PDF converter (version 2006.09.02).]
) (/usr/local/texlive/2013/texmf-dist/tex/generic/oberdiek/pdftexcmds.sty
(/usr/local/texlive/2013/texmf-dist/tex/generic/oberdiek/ifluatex.sty)
(/usr/local/texlive/2013/texmf-dist/tex/generic/oberdiek/ifpdf.sty))
(/usr/local/texlive/2013/texmf-dist/tex/latex/oberdiek/epstopdf-base.sty
(/usr/local/texlive/2013/texmf-dist/tex/latex/oberdiek/grfext.sty
(/usr/local/texlive/2013/texmf-dist/tex/generic/oberdiek/kvdefinekeys.sty))
(/usr/local/texlive/2013/texmf-dist/tex/latex/oberdiek/kvoptions.sty
(/usr/local/texlive/2013/texmf-dist/tex/generic/oberdiek/kvsetkeys.sty
(/usr/local/texlive/2013/texmf-dist/tex/generic/oberdiek/etexcmds.sty)))
(/usr/local/texlive/2013/texmf-dist/tex/latex/latexconfig/epstopdf-sys.cfg))libpng warning: iCCP: known incorrect sRGB profile
<Lemma2.png, id=1, 997.7275pt x 410.53375pt> <use Lemma2.png>
Overfull \hbox (39.88582pt too wide) in paragraph at lines 5--6
[][]
[1{/usr/local/texlive/2013/texmf-var/fonts/map/pdftex/updmap/pdftex.map} <./Lem
ma2.png>] (./pict@[email protected]) )
(see the transcript file for additional information)</usr/local/texlive/2013/te
xmf-dist/fonts/type1/public/amsfonts/cm/cmr10.pfb>
Output written on pict@[email protected] (1 page, 513252 bytes).
SyncTeX written on pict@[email protected].
Transcript written on pict@[email protected].
图像就是上面的那个。