When child pornography is the subject of a search warrant for a cell phone, search of the entire cell phone is permitted. As to a computer, even spreadsheets are subject to search because it’s possible to hide images there. United States v. Sullivan, 2019 U.S. Dist. LEXIS 77446 (W.D. Wash. May 7, 2019):
Regarding electronic spreadsheets, the Government points out that a suspect may copy images into a spreadsheet or change the suffix of a file path to hide the images from search. While it is true there is no indication that Sullivan concealed pornographic images in spreadsheets, Sullivan does not provide authority for the proposition that warrants authorizing the search of electronic evidence must be supported by a specific factual link to each digital file to be searched. Compare the situation to a warrant authorizing the physical search of a home for a small amount of methamphetamine. Law enforcement surely would be permitted to open drawers, lift mattresses, and look inside the freezer for evidence of methamphetamine, even if there was no specific indication in the affidavit that the methamphetamine would be located in any of those places. Similarly, if the Fourth Amendment does not limit a physical search for illicit drugs to a specific location inside a home, assuming the location would plausibly contain the item sought, then neither should this Court limit an electronic search for child pornography to a specific digital location, where probable cause has been found to search the digital device or devices. This proposition is especially true given the wide variety of locations where digital files can be maintained, concealed, or stored.