check package tcl tk

set package_loading_result(img::jpeg) [catch {package require img::jpeg 1.3}]
set package_loading_result(img::gif) [catch {package require img::gif 1.3}]
set package_loading_result(img::png) [catch {package require img::png 1.3}]


# Check for package loading success
set l_failures 0
foreach i_package [array names package_loading_result] {
    if {$package_loading_result($i_package) > 0} {
    incr l_failures
    append l_failed_packages "$i_package \n"
    }
}

if {$l_failures > 0} {
do something here

}