libpng.so.2

locate поможет - если нет libpng.so.2 - то наверняка есть другая версия, на которум ожно сделать слимник - это помогает на 80%, а в остальных случаях - ищи исходники пакета и собирай у себя.

[vic@vicpc vic]$ cat /etc/redhat-release
Red Hat Linux release 7.1 (Seawolf)
[vic@vicpc vic]$ rpm -q --whatprovides libpng.so.2
libpng-1.0.9-1
[vic@vicpc vic]$ rpm -qi libpng
Name        : libpng                       Relocations: (not relocateable)
Version     : 1.0.9                             Vendor: Red Hat, Inc.
Release     : 1                             Build Date: Втр 06 Фев 2001 12:48:56
Install date: Вск 08 Июл 2001 14:36:14      Build Host: porky.devel.redhat.com
Group       : System Environment/Libraries   Source RPM: libpng-1.0.9-1.src.rpm
Size        : 348453                           License: distributable
Packager    : Red Hat, Inc. <http://bugzilla.redhat.com/bugzilla>;
URL         : http://www.libpng.org/pub/png/
Summary     : A library of functions for manipulating PNG image format files.
Description :
The libpng package contains a library of functions for creating and
manipulating PNG (Portable Network Graphics) image format files.  PNG
is a bit-mapped graphics format similar to the GIF format.  PNG was
created to replace the GIF format, since GIF uses a patented data
compression algorithm.

Libpng should be installed if you need to manipulate PNG format image
files.
[vic@vicpc vic]$