Nope. The ImagePickerPage uses qtdocgallery for fetching content, and that’s having a tracker backend as you also speculated. Though not sure could one say it’s specifically tracker that’s causing slowdowns or rather the queries made to it. Might be also some internal handling qtdocgallery. Or even something in the UI layer. But if the gallery app is equally(?) bad then it might be in the middleware side.
For quick reference, run the image picker with dbus-monitor on to get the query:
method call time=1729577276.694994 sender=:1.393 -> destination=org.freedesktop.Tracker3.Miner.Files serial=110 path=/org/freedesktop/Tracker3/Endpoint; interface=org.freedesktop.Tracker3.Endpoint; member=Query
string "SELECT ?p0 ?p1 ?p2 ?p3 ?p4 ?p5 ?p6 ?p7 ?p8 ?p9 ?p10 ?p11 WHERE { GRAPH tracker:Pictures { SELECT ?x as ?p0 nie:isStoredAs(?x) as ?p1 rdf:type(?x) as ?p2 nie:isStoredAs(?x) as ?p3 nie:title(?x) as ?p4 nfo:fileLastModified(nie:isStoredAs(?x)) as ?p5 nfo:fileName(nie:isStoredAs(?x)) as ?p6 nfo:fileSize(nie:isStoredAs(?x)) as ?p7 nie:mimeType(?x) as ?p8 nfo:width(?x) as ?p9 nfo:height(?x) as ?p10 nfo:orientation(?x) as ?p11 WHERE {?x a nmm:Photo . ?x nie:isStoredAs ?file . ?file nie:dataSource/tracker:available true . FILTER(!fn:starts-with(nie:isStoredAs(?x),'file:///home/defaultuser/Music'))} GROUP BY ?x ORDER BY DESC(nfo:fileLastModified(nie:isStoredAs(?x)))}}"
file descriptor
inode: 6406032
type: fifo
array [
]