Sizes are in the return array, here’s an example
Array
(
[ID] => 6308
[id] => 6308
[title] => digitalfantasyart03e
[filename] => digitalfantasyart03e.jpg
[filesize] => 156128
[url] => .../wp-content/uploads/2018/09/digitalfantasyart03e.jpg
[link] => .../hello-world/digitalfantasyart03e/
[alt] =>
[author] => 1
[description] =>
[caption] =>
[name] => digitalfantasyart03e
[status] => inherit
[uploaded_to] => 1
[date] => 2021-09-17 12:44:34
[modified] => 2021-09-17 12:44:34
[menu_order] => 0
[mime_type] => image/jpeg
[type] => image
[subtype] => jpeg
[icon] => .../wp-includes/images/media/default.png
[width] => 1024
[height] => 768
[sizes] => Array
(
[thumbnail] => .../wp-content/uploads/2018/09/digitalfantasyart03e-150x113.jpg
[thumbnail-width] => 150
[thumbnail-height] => 113
[medium] => .../wp-content/uploads/2018/09/digitalfantasyart03e-300x225.jpg
[medium-width] => 300
[medium-height] => 225
[medium_large] => .../wp-content/uploads/2018/09/digitalfantasyart03e-768x576.jpg
[medium_large-width] => 525
[medium_large-height] => 394
[large] => .../wp-content/uploads/2018/09/digitalfantasyart03e.jpg
[large-width] => 525
[large-height] => 394
[1536x1536] => .../wp-content/uploads/2018/09/digitalfantasyart03e.jpg
[1536x1536-width] => 1024
[1536x1536-height] => 768
[2048x2048] => .../wp-content/uploads/2018/09/digitalfantasyart03e.jpg
[2048x2048-width] => 1024
[2048x2048-height] => 768
[twentyseventeen-featured-image] => .../wp-content/uploads/2018/09/digitalfantasyart03e.jpg
[twentyseventeen-featured-image-width] => 1024
[twentyseventeen-featured-image-height] => 768
[twentyseventeen-thumbnail-avatar] => .../wp-content/uploads/2018/09/digitalfantasyart03e-100x100.jpg
[twentyseventeen-thumbnail-avatar-width] => 100
[twentyseventeen-thumbnail-avatar-height] => 100
)
)
