This is not an official Microsoft release. Microsoft ended support for XP in 2014 (and for POSReady 2009 in 2019). "SP4" is a community-made, unofficial update pack.
The "SP4" ISO is essentially a "cumulative update rollup" designed to save users from the "update hell" of installing hundreds of individual patches after a fresh installation. Key integrated components typically include: windows xp sp4 iso archive.org
Let us clarify the biggest misconception immediately: This is not an official Microsoft release
Go to archive.org . Use the search bar exactly: "windows xp sp4" iso Filter by (2019-2021 are most reliable) and Item Size (a full XP ISO should be 650MB to 700MB for CD, or 4.7GB for a DVD-R). or 4.7GB for a DVD-R).