What is the test for ineffective assistance of counsel on appeal?

i.e., there is a reasonable probability that, but for counsel's failings, the result would have been more favorable to the defendant.' [Citation.]" (People v. Johnson (2015) 60 Cal.4th 966, 979-980.)

"'"[T]here is a 'strong presumption that counsel's conduct falls within the wide range of reasonable professional assistance.'"' [Citation.] 'In the usual case, where counsel's trial tactics or strategic reasons for challenged decisions do not appear on the record, we will not find ineffective assistance of counsel on appeal unless there could be no conceivable reason for counsel's acts or omissions.' [Citation.]" (People v. Nguyen, supra, 61 Cal.4th at p. 1051.)

"'"'The admission of allegedly gruesome photographs is basically a question of relevance over which the trial court has broad discretion. [Citation.] "A trial court's decision to admit photographs under Evidence Code section 352 will be upheld on appeal unless the prejudicial effect of such photographs clearly outweighs their probative value."'"' [Citation.]" (People v. Hajek and Vo (2014) 58 Cal.4th 1144, 1215.)