When you have a caged pet, adibags used to show the image of what pet it was not the cage image. Currently better bags only shows the cage.

Additional, pet names cannot be searched for (probably because of same bug why cage is shown?)

Battle pet will always return 'Pet Cage' for name using GetItemInfo(id) you have to get the details from the tooltip

local tooltipData = C_TooltipInfo.GetBagItem(bag, slot) -- or C_TooltipInfo.GetGuildBankItem( tab, slot )
if tooltipData then
	TooltipUtil.SurfaceArgs( tooltipData )
	if tooltipData.battlePetSpeciesID then
		-- tooltipData.battlePetSpeciesID
		-- tooltipData.battlePetLevel
		-- tooltipData.battlePetBreedQuality
		-- tooltipData.battlePetMaxHealth
		-- tooltipData.battlePetPower
		-- tooltipData.battlePetSpeed
		-- tooltipData.battlePetName
	end
end

This is a deal breaker for me.

This is on the list of things to get done. There is a more elegant way of getting the information needed than the tooltip -- it'll get done in the near future.

fixed in #316