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Reports with images can be pretty big, especially when comparing 100+ variables. A comparison of some GOES-R level 2 outputs, 104 variables total, is about 73MiB.

The bulk of the space is going to images. Here's a typical single variable:

Size (KiB)	File
1,452	TOTAL
217	A.png
202	B.png
135	Hex.png
88	Diff.png
80	AbsDiff.png
76	small.A.png
74	small.AbsDiff.png
73	small.B.png
72	Mismatch.png
72	Hist.png
70	small.Diff.png
64	DensityScatter.png
62	small.DensityScatter.png
60	small.Mismatch.png
47	small.Hex.png
27	small.Hist.png
9.6	index.html

These are big enough to be a nuisance to hand around. If we could shrink them, it would be helpful.

Possible techniques to make things smaller:

• Use the option to not generate images if a given variable passes the similarity test.
• Don't generate small.* images; use the originals directly and rescale in browser. It will use more browser memory, CPU, and bandwidth., but I don't think it's significant. This might save about 30% of the space.
• Higher compression levels. perhaps compress_level=9, optimize=True? (default is compress_level=6, optimize=False). Probably not; Going from compression 6 to 9 saves about 2%, turning on optimization saves nothing (indeed, it grows a bit!).

Comparison of compression levels:

Size (B)	Time (s)	compress_level	optimize
1,590,874	2.74	1	False
1,447,641	4.44	6	False
1,414,188	20.09	9	False
1,416,435	19.97	9	True