Expand grayscale JPEGs to RGB(A)

And handle grayscale jpeg example file in test suite.

tests/core/.gitignore

@@ -2,4 +2,6 @@
 *.zip
 *.png
 *.jpg
+*.qoi
+*.pbm
 math_big_test_library.*

tests/core/download_assets.py

@@ -282,6 +282,7 @@ HMAC_DIGESTS = {
 
 	'emblem-1024.jpg':             "d7b7e3ffaa5cda04c667e3742752091d78e02aa2d3c7a63406af679ce810a0a86666b10fcab12cc7ead2fadf2f6c2e1237bc94f892a62a4c218e18a20f96dbe4",
 	'emblem-1024-progressive.jpg': "7a6f4b112bd7189320c58dcddb9129968bcf268798c1e0c4f2243c10b3e3d9a6962c9f142d9fd65f8fb31e9a1e899008cae22b3ffde713250d315499b412e160",
+	'emblem-1024-gray.jpg':        "4c25aaab92451e0452cdb165833b2b5a51978c2571de9d053950944667847666ba198d3001291615acda098ebe45b7d2d53c210c492f077b04a6bfe386f8a5fd",
 
 	'unicode.xml':                 "e0cdc94f07fdbb15eea811ed2ae6dcf494a83d197dafe6580c740270feb0d8f5f7146d4a7d4c2d2ea25f8bd9678bc986123484b39399819a6b7262687959d1ae",
 }

tests/core/image/test_core_image.odin

@@ -51,6 +51,7 @@ Blend_BG_Keep        :: image.Options{.blend_background, .alpha_add_if_missing}
 Return_Metadata      :: image.Options{.return_metadata}
 No_Channel_Expansion :: image.Options{.do_not_expand_channels, .return_metadata}
 
+
 Dims :: struct {
 	width:     int,
 	height:    int,
@@ -2375,6 +2376,13 @@ Basic_JPG_Tests := []Test{
 			{Default,   .Unsupported_Frame_Type, {1024, 1024, 3, 8}, 0x_46a29e0f},
 		},
 	},
+	{
+		"emblem-1024-gray", {
+			{Default,              nil,                 {1024, 1024, 3, 8}, 0x_4115d669},
+			{Alpha_Add,            nil,                 {1024, 1024, 4, 8}, 0x_db496297},
+			{No_Channel_Expansion, .Unsupported_Option, {1024, 1024, 1, 8}, 0},
+		},
+	},
 }
 
 @test